Inhibitors of Checkpoint Kinases

ABSTRACT

The instant invention provides for compounds which comprise fused pyrazoles that inhibit CHK1 activity. The invention also provides for compositions comprising such inhibitory compounds and methods of inhibiting CHK1 activity by administering the compound to a patient in need of treatment of cancer.

BACKGROUND OF THE INVENTION

Cell cycle checkpoints are regulatory pathways that control the order and timing of cell cycle transitions. They ensure that critical events such as DNA replication and chromosome segregation are completed in high fidelity. The regulation of these cell cycle checkpoints is a critical determinant of the manner in which tumor cells respond to many chemotherapies and radiation. Many effective cancer therapies work by causing DNA damage; however, resistance to these agents remains a significant limitation in the treatment of cancer. Of the several mechanisms of drug resistance, an important one is attributed to the prevention of cell cycle progression through the control of critical activation of a checkpoint pathway. This arrests the cell cycle to provide time for repair, and induces the transcription of genes to facilitate repair, thereby avoiding immediate cell death. By abrogating checkpoint arrests at, for example, the G2 checkpoint, it may be possible to synergistically augment tumor cell death induced by DNA damage and circumvent resistance.

Human CHK1 plays a role in regulating cell cycle arrest by phosphorylating the phosphatase cdc25 on Serine 216, which may be involved in preventing activation of cdc2/cyclin B and initiating mitosis. Therefore, inhibition of CHK1 should enhance DNA damaging agents by initiating mitosis before DNA repair is complete and thereby causing tumor cell death. It is an object of the instant invention to provide novel compounds that are inhibitors of CHK1 (also referred to as Chek1).

It is also an object of the present invention to provide pharmaceutical compositions that comprise the novel compounds that are inhibitors of CHK1.

It is also an object of the present invention to provide a method for treating cancer that comprises administering such inhibitors of CHK1 activity.

SUMMARY OF THE INVENTION

The instant invention provides for compounds which comprise fused pyrazoles that inhibit CHK1 activity. The invention also provides for compositions comprising such inhibitory compounds and methods of inhibiting CHK1 activity by administering the compound to a patient in need of treatment of cancer. These fused pyrazoles have improved hemodynamic properties when compared to other fused pyrazoles reported in U.S. Application No. 60/691,694.

DETAILED DESCRIPTION OF THE INVENTION

The compounds of the instant invention are useful in the inhibition of the activity of CHK1. In an embodiment of this invention, the inhibitors of CHK1 activity are illustrated by the Formula A:

wherein:

R¹ is independently selected from H and F, wherein at least one of R¹ is F;

or a pharmaceutically acceptable salt or a stereoisomer thereof.

Specific compounds of the instant invention are:

-   5-(3-amino-2-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-12a); -   5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-15); -   5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-16); and -   5-(3-amino-2,2-difluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-17);     or a pharmaceutically acceptable salt or a stereoisomer thereof.

HCl salts of the instant invention are:

-   5-(3-amino-2-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-12a); -   5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-15); and -   5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-16);     or a stereoisomer thereof.

A TFA salt of the instant invention is:

-   5-(3-amino-2,2-difluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one     (1-17);     or a stereoisomer thereof.

The compounds of the present invention may have asymmetric centers, chiral axes, and chiral planes (as described in: E. L. Eliel and S. H. Wilen, Stereochemistry of Carbon Compounds, John Wiley & Sons, New York, 1994, pages 1119-1190), and occur as racemates, racemic mixtures, and as individual diastereomers, with all possible isomers and mixtures thereof, including optical isomers, being included in the present invention. In addition, the compounds disclosed herein may exist as tautomers and both tautomeric forms are intended to be encompassed by the scope of the invention, even though only one tautomeric structure is depicted.

It is understood that one or more silicon (Si) atoms can be incorporated into the compounds of the instant invention in place of one or more carbon atoms by one of ordinary skill in the art to provide compounds that are chemically stable and that can be readily synthesized by techniques known in the art from readily available starting materials. Carbon and silicon differ in their covalent radius leading to differences in bond distance and the steric arrangement when comparing analogous C-element and Si-element bonds. These differences lead to subtle changes in the size and shape of silicon-containing compounds when compared to carbon. One of ordinary skill in the art would understand that size and shape differences can lead to subtle or dramatic changes in potency, solubility, lack of off target activity, packaging properties, and so on. (Diass, J. O. et al. Organometallics (2006) 5:1188-1198; Showell, G. A. et al. Bioorganic & Medicinal Chemistry Letters (2006) 16:2555-2558).

Included in the instant invention is the free form of compounds of Formula A, as well as the pharmaceutically acceptable salts and stereoisomers thereof. Some of the isolated specific compounds exemplified herein are the protonated salts of amine compounds. The term “free form” refers to the amine compounds in non-salt form. The encompassed pharmaceutically acceptable salts not only include the isolated salts exemplified for the specific compounds described herein, but also all the typical pharmaceutically acceptable salts of the free form of compounds of Formula A. The free form of the specific salt compounds described may be isolated using techniques known in the art. For example, the free form may be regenerated by treating the salt with a suitable dilute aqueous base solution such as dilute aqueous NaOH, potassium carbonate, ammonia and sodium bicarbonate. The free forms may differ from their respective salt forms somewhat in certain physical properties, such as solubility in polar solvents, but the acid and base salts are otherwise pharmaceutically equivalent to their respective free forms for purposes of the invention.

The pharmaceutically acceptable salts of the instant compounds can be synthesized from the compounds of this invention which contain a basic or acidic moiety by conventional chemical methods. Generally, the salts of the basic compounds are prepared either by ion exchange chromatography or by reacting the free base with stoichiometric amounts or with an excess of the desired salt-forming inorganic or organic acid in a suitable solvent or various combinations of solvents. Similarly, the salts of the acidic compounds are formed by reactions with the appropriate inorganic or organic base.

Thus, pharmaceutically acceptable salts of the compounds of this invention include the conventional non-toxic salts of the compounds of this invention as formed by reacting a basic instant compound with an inorganic or organic acid. For example, conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like, as well as salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxy-benzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, trifluoroacetic: (TFA) and the like.

When the compound of the present invention is acidic, suitable “pharmaceutically acceptable salts” refers to salts prepared form pharmaceutically acceptable non-toxic bases including inorganic bases and organic bases. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as arginine, betaine caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine tripropylamine, tromethamine and the like.

The preparation of the pharmaceutically acceptable salts described above and other typical pharmaceutically acceptable salts is more fully described by Berg et al, “Pharmaceutical Salts,” J. Pharm. Sci., 1977:66:1-19.

It will also be noted that the compounds of the present invention are potentially internal salts or zwitterions, since under physiological conditions a deprotonated acidic moiety in the compound, such as a carboxyl group, may be anionic, and this electronic charge might then be balanced off internally against the cationic charge of a protonated or alkylated basic moiety, such as a quaternary nitrogen atom.

UTILITY

The compounds, compositions and methods provided herein are particularly deemed useful for the treatment of cancer. Cancers that may be treated by the compounds, compositions and methods of the invention include, but are not limited to: Cardiac: sarcoma (angiosarcoma, fibrosarcoma, rhabdomyosarcoma, liposarcoma), myxoma, rhabdomyoma, fibroma, lipoma and teratoma; Lung: bronchogenic carcinoma (squamous cell, undifferentiated small cell, undifferentiated large cell, adenocarcinoma), alveolar (bronchiolar) carcinoma, bronchial adenoma, sarcoma, lymphoma, chondromatous hamartoma, mesothelioma, non-small cell lung; Gastrointestinal: esophagus (squamous cell carcinoma, adenocarcinoma, leiomyosarcoma, lymphoma), stomach (carcinoma, lymphoma, leiomyosarcoma), pancreas (ductal adenocarcinoma, insulinoma, glucagonoma, gastrinoma, carcinoid tumors, vipoma), small bowel (adenocarcinoma, lymphoma, carcinoid tumors, Karposi's sarcoma, leiomyoma, hemangioma, lipoma, neurofibroma, fibroma), large bowel (adenocarcinoma, tubular adenoma, villous adenoma, hamartoma, leiomyoma) colon, colorectal, rectal; Genitourinary tract: kidney (adenocarcinoma, Wilm's tumor [nephroblastoma], lymphoma, leukemia), bladder and urethra (squamous cell carcinoma, transitional cell carcinoma, adenocarcinoma), prostate (adenocarcinoma, sarcoma), testis (seminoma, teratoma, embryonal carcinoma, teratocarcinoma, choriocarcinoma, sarcoma, interstitial cell carcinoma, fibroma, fibroadenoma, adenomatoid tumors, lipoma); Liver: hepatoma (hepatocellular carcinoma), cholangiocarcinoma, hepatoblastoma, angiosarcoma, hepatocellular adenoma, hemangioma; Bone: osteogenic sarcoma (osteosarcoma), fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma, Ewing's sarcoma, malignant lymphoma (reticulum cell sarcoma), multiple myeloma, malignant giant cell tumor chordoma, osteochronfroma (osteocartilaginous exostoses), benign chondroma, chondroblastoma, chondromyxofibroma, osteoid osteoma and giant cell tumors; Nervous system: skull (osteoma, hemangioma, granuloma, xanthoma, osteitis deformans), meninges (meningioma, meningiosarcoma, gliomatosis), brain (astrocytoma, medulloblastoma, glioma, ependymoma, germinoma [pinealoma], glioblastoma multiform, oligodendroglioma, schwannoma, retinoblastoma, congenital tumors), spinal cord neurofibroma, meningioma, glioma, sarcoma); Gynecological: uterus (endometrial carcinoma), cervix (cervical carcinoma, pre-tumor cervical dysplasia), ovaries (ovarian carcinoma [serous cystadenocarcinoma, mucinous cystadenocarcinoma, unclassified carcinoma], granulosa-thecal cell tumors, Sertoli-Leydig cell tumors, dysgerminoma, malignant teratoma), vulva (squamous cell carcinoma, intraepithelial carcinoma, adenocarcinoma, fibrosarcoma, melanoma), vagina (clear cell carcinoma, squamous cell carcinoma, botryoid sarcoma (embryonal rhabdomyosarcoma), fallopian tubes (carcinoma), breast; Hematologic: blood (myeloid leukemia [acute and chronic], acute lymphoblastic leukemia, chronic lymphocytic leukemia, myeloproliferative diseases, multiple myeloma, myelodysplastic syndrome), Hodgkin's disease, non-Hodgkin's lymphoma [malignant lymphoma]; Skin: malignant melanoma, basal cell carcinoma, squamous cell carcinoma, Karposi's sarcoma, moles dysplastic nevi, lipoma, angioma, dermatofibroma, keloids, psoriasis; and Adrenal glands: neuroblastoma. Thus, the term “cancerous cell” as provided herein, includes a cell afflicted by any one of the above-identified conditions.

Cancers that may be treated by the compounds, compositions and methods of the invention include, but are not limited to: breast, prostate, colon, colorectal, lung, non-small cell lung, brain, testicular, stomach, pancrease, skin, small intestine, large intestine, throat, head and neck, oral, bone, liver, bladder, kidney, thyroid and blood.

Cancers that may be treated by the compounds, compositions and methods of the invention include: breast, prostate, colon, ovarian, colorectal and lung.

Cancers that may be treated by the compounds, compositions and methods of the invention include: breast, colon, (colorectal) and lung.

Cancers that may be treated by the compounds, compositions and methods of the invention include: lymphoma and leukemia.

The compounds of the invention are also useful in preparing a medicament that is useful in treating cancer.

The compounds of this invention may be administered to mammals, including humans, either alone or, in combination with pharmaceutically acceptable carriers, excipients or diluents, in a pharmaceutical composition, according to standard pharmaceutical practice. The compounds can be administered orally or parenterally, including the intravenous, intramuscular, intraperitoneal, subcutaneous, rectal and topical routes of administration.

The pharmaceutical compositions containing the active ingredient may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, microcrystalline cellulose, sodium crosscarmellose, corn starch, or alginic acid; binding agents, for example starch, gelatin, polyvinyl-pyrrolidone or acacia, and lubricating agents, for example, magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to mask the unpleasant taste of the drug or delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a water soluble taste masking material such as hydroxypropylmethyl-cellulose or hydroxypropylcellulose, or a time delay material such as ethyl cellulose, cellulose acetate buryrate may be employed.

Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water soluble carrier such as polyethyleneglycol or an oil medium, for example peanut oil, liquid paraffin, or olive oil.

Aqueous suspensions contain the active material in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethyl-cellulose, sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethylene-oxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose, saccharin or aspartame.

Oily suspensions may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant such as butylated hydroxyanisol or alpha-tocopherol.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.

The pharmaceutical compositions of the invention may also be in the form of an oil-in-water emulsion. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring phosphatides, for example soy bean lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan monooleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions may also contain sweetening, flavouring agents, preservatives and antioxidants.

Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative, flavoring and coloring agents and antioxidant.

The pharmaceutical compositions may be in the form of sterile injectable aqueous solutions. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution.

The sterile injectable preparation may also be a sterile injectable oil-in-water microemulsion where the active ingredient is dissolved in the oily phase. For example, the active ingredient may be first dissolved in a mixture of soybean oil and lecithin. The oil solution then introduced into a water and glycerol mixture and processed to form a microemulation.

The injectable solutions or microemulsions may be introduced into a patient's blood-stream by local bolus injection. Alternatively, it may be advantageous to administer the solution or microemulsion in such a way as to maintain a constant circulating concentration of the instant compound. In order to maintain such a constant concentration, a continuous intravenous delivery device may be utilized. An example of such a device is the Deltec CADD-PLUS™ model 5400 intravenous pump.

The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleagenous suspension for intramuscular and subcutaneous administration. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example as a solution in 1,3-butane diol. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.

Compounds of the instant invention may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials include cocoa butter, glycerinated gelatin, hydrogenated vegetable oils, mixtures of polyethylene glycols of various molecular weights and fatty acid esters of polyethylene glycol.

For topical use, creams, ointments, jellies, solutions or suspensions, etc., containing the compound of Formula A are employed. (For purposes of this application, topical application shall include mouth washes and gargles.)

The compounds for the present invention can be administered in intranasal form via topical use of suitable intranasal vehicles and delivery devices, or via transdermal routes, using those forms of transdermal skin patches well known to those of ordinary skill in the art. To be administered in the form of a transdermal delivery system, the dosage administration will, of course, be continuous rather than intermittent throughout the dosage regimen. Compounds of the present invention may also be delivered as a suppository employing bases such as cocoa butter, glycerinated gelatin, hydrogenated vegetable oils, mixtures of polyethylene glycols of various molecular weights and fatty acid esters of polyethylene glycol.

When a composition according to this invention is administered into a human subject, the daily dosage will normally be determined by the prescribing physician with the dosage generally varying according to the age, weight, and response of the individual patient, as well as the severity of the patient's symptoms.

In an embodiment, a suitable amount of an inhibitor of CHK1 is administered to a mammal undergoing treatment for cancer. Administration occurs in an amount of inhibitor of between about 0.1 mg/kg of body weight to about 60 mg/kg of body weight per day, or between 0.5 mg/kg of body weight to about 40 mg/kg of body weight per day. Another therapeutic dosage that comprises the instant composition includes from about 0.01 mg to about 1000 mg of inhibitor of CHK1. In another embodiment, the dosage comprises from about 1 mg to about 1000 mg of inhibitor of CHK1.

The instant compounds are also useful in combination with therapeutic, chemotherapeutic and anti-cancer agents. Combinations of the presently disclosed compounds with therapeutic, chemotherapeutic and anti-cancer agents are within the scope of the invention. Examples of such agents can be found in Cancer Principles and Practice of Oncology by V. T. Devita and S. Hellman (editors), 6^(th) edition (Feb. 15, 2001), Lippincott Williams & Wilkins Publishers. A person of ordinary skill in the art would be able to discern which combinations of agents would be useful based on the particular characteristics of the drugs and the cancer involved. Such agents include the following: estrogen receptor modulators, androgen receptor modulators, retinoid receptor modulators, cytotoxic/cytostatic agents, antiproliferative agents, prenyl-protein transferase inhibitors, HMG-CoA reductase inhibitors and other angiogenesis inhibitors, HIV protease inhibitors, reverse transcriptase inhibitors, inhibitors of cell proliferation and survival signaling, bisphosphonates, aromatase inhibitors, siRNA therapeutics, γ-secretase inhibitors, agents that interfere with receptor tyrosine kinases (RTEKs) and agents that interfere with cell cycle checkpoints. The instant compounds are particularly useful when co-administered with radiation therapy.

“Estrogen receptor modulators” refers to compounds that interfere with or inhibit the binding of estrogen to the receptor, regardless of mechanism. Examples of estrogen receptor modulators include, but are not limited to, tamoxifen, raloxifene, idoxifene, LY353381, LY117081, toremifene, fulvestrant, 4-[7-(2,2-dimethyl-1-oxopropoxy-4-methyl-2-[4-[2-(1-piperidinyl)ethoxy]phenyl]-2H-1-benzopyran-3-yl]-phenyl-2,2-dimethylpropanoate, 4,4′-dihydroxybenzophenone-2,4-dinitrophenyl-hydrazone, and SH646.

“Androgen receptor modulators” refers to compounds which interfere or inhibit the binding of androgens to the receptor, regardless of mechanism. Examples of androgen receptor modulators include finasteride and other 5α-reductase inhibitors, nilutamide, flutamide, bicalutamide, liarozole, and abiraterone acetate.

“Retinoid receptor modulators” refers to compounds which interfere or inhibit the binding of retinoids to the receptor, regardless of mechanism. Examples of such retinoid receptor modulators include bexarotene, tretinoin, 13-cis-retinoic acid, 9-cis-retinoic acid, α-difluoromethylomithine, ILX23-7553, trans-N-(4′-hydroxyphenyl) retinamide, and N-4-carboxyphenyl retinamide.

“Cytotoxic/cytostatic agents” refer to compounds which cause cell death or inhibit cell proliferation primarily by interfering directly with the cell's functioning or inhibit or interfere with cell myosis, including alkylating agents, tumor necrosis factors, intercalators, hypoxia activatable compounds, microtubule inhibitors/microtubule-stabilizing agents, inhibitors of mitotic kinesins, histone deacetylase inhibitors, inhibitors of kinases involved in mitotic progression, inhibitors of kinases involved in growth factor and cytokine signal transduction pathways, antimetabolites, biological response modifiers, hormonal/anti-hormonal therapeutic agents, haematopoietic growth factors, monoclonal antibody targeted therapeutic agents, topoisomerase inhibitors, proteosome inhibitors, ubiquitin ligase inhibitors, and aurora kinase inhibitors.

Examples of cytotoxic/cytostatic agents include, but are not limited to, sertenef, cachectin, ifosfamide, tasonermin, lonidamine, carboplatin, altretamine, prednimustine, dibromodulcitol, ranimustine, fotemustine, nedaplatin, oxaliplatin, temozolomide, heptaplatin, estramustine, improsulfan tosilate, trofosfamide, nimustine, dibrospidium chloride, pumitepa, lobaplatin, satraplatin, profiromycin, cisplatin, irofulven, dexifosfamide, cis-aminedichloro(2-methyl-pyridine)platinum, benzylguanine, glufosfamide, GPX100, (trans, trans, trans)-bis-mu-(hexane-1,6-diamine)-mu-[diamine-platinum(II)]bis[diamine(chloro)platinum(II)]tetrachloride, diarizidinylspermine, arsenic trioxide, 1-(11-dodecylamino-10-hydroxyundecyl)-3,7-dimethylxanthine, zorubicin, idarubicin, daunorubicin, bisantrene, mitoxantrone, pirarubicin, pinafide, valrubicin, amrubicin, antineoplaston, 3′-deamino-3′-morpholino-13-deoxo-10-hydroxycaminomycin, annamycin, galarubicin, elinafide, MEN10755, 4-demethoxy-3-deamino-3-aziridinyl-4-methylsulphonyl-daunorubicin (see WO 00/50032), Raf kinase inhibitors (such as Bay43-9006) and mTOR inhibitors (such as Wyeth's CCI-779).

An example of a hypoxia activatable compound is tirapazamine.

Examples of proteosome inhibitors include but are not limited to lactacystin and MLN-341 (Velcade).

Examples of microtubule inhibitors/microtubule-stabilising agents include paclitaxel, vindesine sulfate, 3′,4′-didehydro-4′-deoxy-8′-norvincaleukoblastine, docetaxol, rhizoxin, dolastatin, mivobulin isethionate, auristatin, cemadotin, RPR109881, BMS184476, vinflunine, cryptophycin, 2,3,4,5,6-pentafluoro-N-(3-fluoro-4-methoxyphenyl)benzene sulfonamide, anhydrovinblastine, N,N-dimethyl-L-valyl-L-valyl-N-methyl-L-valyl-L-prolyl-L-proline-t-butylamide, TDX258, the epothilones (see for example U.S. Pat. Nos. 6,284,781 and 6,288,237) and BMS188797. In an embodiment the epothilones are not included in the microtubule inhibitors/microtubule-stabilising agents.

Some examples of topoisomerase inhibitors are topotecan, hycaptamine, irinotecan, rubitecan, 6-ethoxypropionyl-3′,4′-O-exo-benzylidene-chartreusin, 9-methoxy-N,N-dimethyl-5-nitropyrazolo[3,4,5-kl]acridine-2-(6H) propanamine, 1-amino-9-ethyl-5-fluoro-2,3-dihydro-9-hydroxy-4-methyl-1H,12H-benzo[de]pyrano[3′,4′:b,7]-indolizino[1,2b]quinoline-10,13(9H,15H)dione, lurtotecan, 7-[2-(N-isopropylamino)ethyl]-(20S)camptothecin, BNP1350, BNPI1100, BN80915, BN80942, etoposide phosphate, teniposide, sobuzoxane, 2′-dimethylamino-2′-deoxy-etoposide, GL331, N-[2-(dimethylamino)ethyl]-9-hydroxy-5,6-dimethyl-6H-pyrido[4,3-b]carbazole-1-carboxamide, asulacrine, (5a,5aB,8aa,9b)-9-[2-[N-[2-(dimethylamino)ethyl]-N-methylamino]ethyl]-5-[4-hydroxy-3,5-dimethoxyphenyl]-5,5a,6,8,8a,9-hexohydrofuro(3′,4′:6,7)naphtho(2,3-d)-1,3-dioxol-6-one, 2,3-(methylenedioxy)-5-methyl-7-hydroxy-8-methoxybenzo[c]-phenanthridinium, 6,9-bis[(2-aminoethyl)amino]benzo[g]isoquinoline-5,10-dione, 5-(3-aminopropylamino)-7,10-dihydroxy-2-(2-hydroxyethylaminomethyl)-6H-pyrazolo[4,5,1-de]acridin-6-one, N-[1[2(diethylamino)ethylamino]-7-methoxy-9-oxo-9H-thioxanthen-4-ylmethyl]formamide, N-(2-(dimethylamino)ethyl)acridine-4-carboxamide, 6-[[2-(dimethylamino)ethyl]amino]-3-hydroxy-7H-indeno[2,1-c]quinolin-7-one, and dimesna.

Examples of inhibitors of mitotic kinesins, and in particular the human mitotic kinesin KSP, are described in Publications WO03/039460, WO03/050064, WO03/050122, WO03/049527, WO03/049679, WO03/049678, WO04/039774, WO03/079973, WO03/099211, WO03/105855, WO03/106417, WO04/037171, WO04/058148, WO04/058700, WO04/126699, WO05/018638, WO05/019206, WO05/019205, WO05/018547, WO05/017190, US2005/0176776. In an embodiment inhibitors of mitotic kinesins include, but are not limited to inhibitors of KSP, inhibitors of MKLP1, inhibitors of CENP-E, inhibitors of MCAK and inhibitors of Rab6-KIFL.

Examples of “histone deacetylase inhibitors” include, but are not limited to, SAHA, TSA, oxamflatin, PXD101, MG98 and scriptaid. Further reference to other histone deacetylase inhibitors may be found in the following manuscript; Miller, T. A. et al., J. Med. Chem. 46(24):5097-5116 (2003).

“Inhibitors of kinases involved in mitotic progression” include, but are not limited to, inhibitors of aurora kinase, inhibitors of Polo-like kinases (PLK; in particular inhibitors of PLK-1), inhibitors of bub-1 and inhibitors of bub-R1. An example of an “aurora kinase inhibitor” is VX-680.

“Antiproliferative agents” includes antisense RNA and DNA oligonucleotides such as G3139, ODN698, RVASKRAS, GEM231, and INX3001, and antimetabolites such as enocitabine, carmofur, tegafur, pentostatin, doxifluridine, trimetrexate, fludarabine, capecitabine, galocitabine, cytarabine ocfosfate, fosteabine sodium hydrate, raltitrexed, paltitrexid, emitefur, tiazofurin, decitabine, nolatrexed, pemetrexed, nelzarabine, 2′-deoxy-2′-methylidenecytidine, 2′-fluoromethylene-2′-deoxycytidine, N-[5-(2,3-dihydro-benzofuryl)sulfonyl]-N′-(3,4-dichlorophenyl)urea, N6-[4-deoxy-4-[N2-[2(E),4(E)-tetradecadienoyl]glycylamino]-L-glycero-B-L-manno-heptopyranosyl]adenine, aplidine, ecteinascidin, troxacitabine, 4-[2-amino-4-oxo-4,6,7,8-tetrahydro-3H-pyrimidino[5,4-b][1,4]thiazin-6-yl-(S)-ethyl]-2,5-thienoyl-L-glutamic acid, aminopterin, 5-fluorouracil, alanosine, 11-acetyl-8-(carbamoyloxymethyl)-4-formyl-6-methoxy-14-oxa-1,11-diazatetracyclo(7.4.1.0.0)-tetradeca-2,4,6-trien-9-yl acetic acid ester, swainsonine, lometrexol, dexrazoxane, methioninase, 2′-cyano-2′-deoxy-N4-palmitoyl-1-B-D-arabino furanosyl cytosine, 3-aminopyridine-2-carboxaldehyde thiosemicarbazone and trastuzumab.

Examples of monoclonal antibody targeted therapeutic agents include those therapeutic agents which have cytotoxic agents or radioisotopes attached to a cancer cell specific or target cell specific monoclonal antibody. Examples include Bexxar.

“HMG-CoA reductase inhibitors” refers to inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase. Examples of HMG-CoA reductase inhibitors that may be used include but are not limited to lovastatin (MEVACOR®; see U.S. Pat. Nos. 4,231,938, 4,294,926 and 4,319,039), simvastatin (ZOCOR®; see U.S. Pat. Nos. 4,444,784, 4,820,850 and 4,916,239), pravastatin (PRAVACHOL®; see U.S. Pat. Nos. 4,346,227, 4,537,859, 4,410,629, 5,030,447 and 5,180,589), fluvastatin (LESCOL®; see U.S. Pat. Nos. 5,354,772, 4,911,165, 4,929,437, 5,189,164, 5,118,853, 5,290,946 and 5,356,896), atorvastatin (LIPITOR®; see U.S. Pat. Nos. 5,273,995, 4,681,893, 5,489,691 and 5,342,952) and cerivastatin (also known as rivastatin and BAYCHOL®; see U.S. Pat. No. 5,177,080). The structural formulas of these and additional HMG-CoA reductase inhibitors that may be used in the instant methods are described at page 87 of M. Yalpani, “Cholesterol Lowering Drugs”, Chemistry & Industry, pp. 85-89 (5 Feb. 1996) and U.S. Pat. Nos. 4,782,084 and 4,885,314. The term HMG-CoA reductase inhibitor as used herein includes all pharmaceutically acceptable lactone and open-acid forms (i.e., where the lactone ring is opened to form the free acid) as well as salt and ester forms of compounds which have HMG-CoA reductase inhibitory activity, and therefor the use of such salts, esters, open-acid and lactone forms is included within the scope of this invention.

“Prenyl-protein transferase inhibitor” refers to a compound which inhibits any one or any combination of the prenyl-protein transferase enzymes, including farnesyl-protein transferase (FPTase), geranylgeranyl-protein transferase type I (GGPTase-I), and geranylgeranyl-protein transferase type-II (GGPTase-II, also called Rab GGPTase).

Examples of prenyl-protein transferase inhibitors can be found in the following publications and patents: WO 96/30343, WO 97/18813, WO 97/21701, WO 97/23478, WO 97/38665, WO 98/28980, WO 98/29119, WO 95/32987, U.S. Pat. No. 5,420,245, U.S. Pat. No. 5,523,430, U.S. Pat. No. 5,532,359, U.S. Pat. No. 5,510,510, U.S. Pat. No. 5,589,485, U.S. Pat. No. 5,602,098, European Patent Publ. 0 618 221, European Patent Publ. 0 675 112, European Patent Publ. 0 604 181, European Patent Publ. 0 696 593, WO 94/19357, WO 95/08542, WO 95/11917, WO 95/12612, WO 95/12572, WO 95/10514, U.S. Pat. No. 5,661,152, WO 95/10515, WO 95/10516, WO 95/24612, WO 95/34535, WO 95/25086, WO 96/05529, WO 96/06138, WO 96/06193, WO 96/16443, WO 96/21701, WO 96/21456, WO 96/22278, WO 96/24611, WO 96/24612, WO 96/05168, WO 96/05169, WO 96/00736, U.S. Pat. No. 5,571,792, WO 96/17861, WO 96/33159, WO 96/34850, WO 96/34851, WO 96/30017, WO 96/30018, WO 96/30362, WO 96/30363, WO 96/31111, WO 96/31477, WO 96/31478, WO 96/31501, WO 97/00252, WO 97/03047, WO 97/03050, WO 97/04785; WO 97/02920, WO 97/17070, WO 97/23478, WO 97/26246, WO 97/30053, WO 97/44350, WO 98/02436, and U.S. Pat. No. 5,532,359. For an example of the role of a prenyl-protein transferase inhibitor on angiogenesis see European J. of Cancer, Vol. 35, No. 9, pp. 1394-1401 (1999).

“Angiogenesis inhibitors” refers to compounds that inhibit the formation of new blood vessels, regardless of mechanism. Examples of angiogenesis inhibitors include, but are not limited to, tyrosine kinase inhibitors, such as inhibitors of the tyrosine kinase receptors Flt-1 (VEGFR1) and Flk-1/KDR (VEGFR2), inhibitors of epidermal-derived, fibroblast-derived, or platelet derived growth factors, MMP (matrix metalloprotease) inhibitors, integrin blockers, interferon-α, interleukin-12, pentosan polysulfate, cyclooxygenase inhibitors, including nonsteroidal anti-inflammatories (NSAIDs) like aspirin and ibuprofen as well as selective cyclooxy-genase-2 inhibitors like celecoxib and rofecoxib (PNAS, Vol. 89, p. 7384 (1992); JNCI, Vol. 69, p. 475 (1982); Arch. Opthalmol., Vol. 108, p. 573 (1990); Anat. Rec., Vol. 238, p. 68 (1994); FEBS Letters, Vol. 372, p. 83 (1995); Clin. Orthop. Vol. 313, p. 76 (1995); J. Mol. Endocrinol., Vol. 16, p. 107 (1996); Jpn. J. Pharmacol., Vol. 75, p. 105 (1997); Cancer Res., Vol. 57, p. 1625 (1997); Cell, Vol. 93, p. 705 (1998); Intl. J. Mol. Med., Vol. 2, p. 715 (1998); J. Biol. Chem., Vol. 274, p. 9116 (1999)), steroidal anti-inflammatories (such as corticosteroids, mineralocorticoids, dexamethasone, prednisone, prednisolone, methylpred, betamethasone), carboxyamidotriazole, combretastatin A-4, squalamine, 6-O-chloroacetyl-carbonyl)-fumagillol, thalidomide, angiostatin, troponin-1, angiotensin II antagonists (see Fernandez et al., J. Lab. Clin. Med. 105:141-145 (1985)), and antibodies to VEGF (see, Nature Biotechnology, Vol. 17, pp. 963-968 (October 1999); Kim et al., Nature, 362, 841-844 (1993); WO 00/44777; and WO 00/61186).

Other therapeutic agents that modulate or inhibit angiogenesis and may also be used in combination with the compounds of the instant invention include agents that modulate or inhibit the coagulation and fibrinolysis systems (see review in Clin. Chem. La. Med. 38:679-692 (2000)). Examples of such agents that modulate or inhibit the coagulation and fibrinolysis pathways include, but are not limited to, heparin (see Thromb. Haemost. 80: 10-23 (1998)), low molecular weight heparins and carboxypeptidase U inhibitors (also known as inhibitors of active thrombin activatable fibrinolysis inhibitor [TAFIa]) (see Thrombosis Res. 101:329-354 (2001)). TAFIa inhibitors have been described in U.S. Ser. Nos. 60/310,927 (filed Aug. 8, 2001) and 60/349,925 (filed Jan. 18, 2002).

“Agents that interfere with cell cycle checkpoints” refer to compounds that inhibit protein kinases that transduce cell cycle checkpoint signals, thereby sensitizing the cancer cell to DNA damaging agents. Such agents include inhibitors of ATR, ATM, the CHK11 and CHK12 kinases and cdk and cdc kinase inhibitors and are specifically exemplified by 7-hydroxystaurosporin, flavopiridol, CYC202 (Cyclacel) and BMS-387032.

“Agents that interfere with receptor tyrosine kinases (RTKs)” refer to compounds that inhibit RTKs and therefore mechanisms involved in oncogenesis and tumor progression. Such agents include inhibitors of c-Kit, Eph, PDGF, Flt3 and c-Met. Further agents include inhibitors of RTKs as described by Bume-Jensen and Hunter, Nature, 411:355-365, 2001.

“Inhibitors of cell proliferation and survival signalling pathway” refer to compounds that inhibit signal transduction cascades downstream of cell surface receptors. Such agents include inhibitors of serine/threonine kinases (including but not limited to inhibitors of Akt such as described in WO 02/083064, WO 02/083139, WO 02/083140, US 2004-0116432, WO 02/083138, US 2004-0102360, WO 03/086404, WO 03/086279, WO 03/086394, WO 03/084473, WO 03/086403, WO 2004/041162, WO 2004/096131, WO 2004/096129, WO 2004/096135, WO 2004/096130, WO 2005/100356, WO 2005/100344, US 2005/029941, US 2005/44294, US 2005/43361, 60/734,188, 60/652,737, 60/670,469), inhibitors of Raf kinase (for example BAY-43-9006), inhibitors of MEK (for example CI-1040 and PD-098059), inhibitors of mTOR (for example Wyeth CCI-779), and inhibitors of PI3K (for example LY294002).

As described above, the combinations with NSAID's are directed to the use of NSAID's which are potent COX-2 inhibiting agents. For purposes of this specification an NSAID is potent if it possesses an IC₅₀ for the inhibition of COX-2 of 1 μM or less as measured by cell or microsomal assays.

The invention also encompasses combinations with NSAID's which are selective COX-2 inhibitors. For purposes of this specification NSAID's which are selective inhibitors of COX-2 are defined as those which possess a specificity for inhibiting COX-2 over COX-1 of at least 100 fold as measured by the ratio of IC₅₀ for COX-2 over IC₅₀ for COX-1 evaluated by cell or microsomal assays. Such compounds include, but are not limited to those disclosed in U.S. Pat. No. 5,474,995, U.S. Pat. No. 5,861,419, U.S. Pat. No. 6,001,843, U.S. Pat. No. 6,020,343, U.S. Pat. No. 5,409,944, U.S. Pat. No. 5,436,265, U.S. Pat. No. 5,536,752, U.S. Pat. No. 5,550,142, U.S. Pat. No. 5,604,260, U.S. Pat. No. 5,698,584, U.S. Pat. No. 5,710,140, WO 94/15932, U.S. Pat. No. 5,344,991, U.S. Pat. No. 5,134,142, U.S. Pat. No. 5,380,738, U.S. Pat. No. 5,393,790, U.S. Pat. No. 5,466,823, U.S. Pat. No. 5,633,272 and U.S. Pat. No. 5,932,598, all of which are hereby incorporated by reference.

Inhibitors of COX-2 that are particularly useful in the instant method of treatment are: 3-phenyl-4-(4-(methylsulfonyl)phenyl)-2-(5H)-furanone; and 5-chloro-3-(4-methylsulfonyl)phenyl-2-(2-methyl-5-pyridinyl)pyridine; or a pharmaceutically acceptable salt thereof.

Compounds that have been described as specific inhibitors of COX-2 and are therefore useful in the present invention include, but are not limited to, the following: parecoxib, BEXTRA® and CELEBREX® or a pharmaceutically acceptable salt thereof.

Other examples of angiogenesis inhibitors include, but are not limited to, endostatin, ukrain, ranpimase, IM862, 5-methoxy-4-[2-methyl-3-(3-methyl-2-butenyl)oxiranyl]-1-oxaspiro[2,5]oct-6-yl(chloroacetyl)carbamate, acetyldinanaline, 5-amino-1-[[3,5-dichloro-4-(4-chlorobenzoyl)phenyl]methyl]-1H-1,2,3-triazole-4-carboxamide, CM101, squalamine, combretastatin, RPI4610, NX31838, sulfated mannopentaose phosphate, 7,7-(carbonyl-bis[imino-N-methyl-4,2-pyrrolocarbonylimino[N-methyl-4,2-pyrrole]-carbonylimino]-bis-(1,3-naphthalene disulfonate), and 3-[(2,4-dimethylpyrrol-5-yl)methylene]-2-indolinone (SU5416).

As used above, “integrin blockers” refers to compounds which selectively antagonize, inhibit or counteract binding of a physiological ligand to the α_(v)β₃ integrin, to compounds which selectively antagonize, inhibit or counteract binding of a physiological ligand to the αvβ5 integrin, to compounds which antagonize, inhibit or counteract binding of a physiological ligand to both the α_(v)β₃ integrin and the α_(v)β₅ integrin, and to compounds which antagonize, inhibit or counteract the activity of the particular integrin(s) expressed on capillary endothelial cells. The term also refers to antagonists of the α_(v)β₆, α_(v)β₈, α₁β₁, α₂β₁, α₅β₁, α₆β₁ and α₆β₄ integrins. The term also refers to antagonists of any combination of α_(v)β₃, α_(v)β₅, α_(v)β₆, α_(v)β₈, α₁β₁, α₂β₁, α₅β₁, α₆β₁ and α₆β₄ integrins.

Some specific examples of tyrosine kinase inhibitors include N-(trifluoromethylphenyl)-5-methylisoxazol-4-carboxamide, 3-[(2,4-dimethylpyrrol-5-yl)methylidenyl)indolin-2-one, 17-(allylamino)-17-demethoxygeldanamycin, 4-(3-chloro-4-fluorophenylamino)-7-methoxy-6-[3-(4-morpholinyl)propoxyl]quinazoline, N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)-4-quinazolinamine, BIBX1382, 2,3,9,10,11,12-hexahydro-10-(hydroxymethyl)-10-hydroxy-9-methyl-9,12-epoxy-1H-diindolo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-i][1,6]benzodiazocin-1-one, SH268, genistein, STI571, CEP2563, 4-(3-chlorophenylamino)-5,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidinemethane sulfonate, 4-(3-bromo-4-hydroxyphenyl)amino-6,7-dimethoxyquinazoline, 4-(4′-hydroxyphenyl)amino-6,7-dimethoxyquinazoline, SU6668, STI1571A, N-4-chlorophenyl-4-(4-pyridylmethyl)-1-phthalazinamine, and EMD121974.

Combinations with compounds other than anti-cancer compounds are also encompassed in the instant methods. For example, combinations of the instantly claimed compounds with PPAR-γ (i.e., PPAR-gamma) agonists and PPAR-δ (i.e., PPAR-delta) agonists are useful in the treatment of certain malingnancies. PPAR-γ and PPAR-δ are the nuclear peroxisome proliferator-activated receptors γ and δ. The expression of PPAR-γ on endothelial cells and its involvement in angiogenesis has been reported in the literature (see J. Cardiovasc. Pharmacol. 1998; 31:909-913; J. Biol. Chem. 1999; 274:9116-9121; Invest. Opthalmol. Vis. Sci. 2000; 41:2309-2317). More recently, PPAR-γ agonists have been shown to inhibit the angiogenic response to VEGF in vitro; both troglitazone and rosiglitazone maleate inhibit the development of retinal neovasculatization in mice. (Arch. Ophthamol. 2001; 119:709-717). Examples of PPAR-γ agonists and PPAR-γ/α agonists include, but are not limited to, thiazolidinediones (such as DRF2725, CS-011, troglitazone, rosiglitazone, and pioglitazone), fenofibrate, gemfibrozil, clofibrate, GW2570, SB219994, AR-H039242, JIT-501, MCC-555, GW2331, GW409544, NN2344, KRP297, NP0110, DRF4158, NN622, G1262570, PNU182716, DRF552926, 2-[(5,7-dipropyl-3-trifluoromethyl-1,2-benzisoxazol-6-yl)oxy]-2-methylpropionic acid (disclosed in U.S. Ser. No. 09/782,856), and 2(R)-7-(3-(2-chloro-4-(4-fluorophenoxy)phenoxy)propoxy)-2-ethylchromane-2-carboxylic acid (disclosed in U.S. Ser. No. 60/235,708 and 60/244,697).

Another embodiment of the instant invention is the use of the presently disclosed compounds in combination with gene therapy for the treatment of cancer. For an overview of genetic strategies to treating cancer see Hall et al (Am. J. Hum. Genet. 61:785-789, 1997) and Kufe et al (Cancer Medicine, 5th Ed, pp 876-889, BC Decker, Hamilton 2000). Gene therapy can be used to deliver any tumor suppressing gene. Examples of such genes include, but are not limited to, p 53, which can be delivered via recombinant virus-mediated gene transfer (see U.S. Pat. No. 6,069,134, for example), a uPA/uPAR antagonist (“Adenovirus-Mediated Delivery of a uPA/uPAR Antagonist Suppresses Angiogenesis-Dependent Tumor Growth and Dissemination in Mice,” Gene Therapy, August 1998; 5(8):1105-13), and interferon gamma (J. Immunol. 2000; 164:217-222).

The compounds of the instant invention may also be administered in combination with an inhibitor of inherent multidrug resistance (MDR), in particular MDR associated with high levels of expression of transporter proteins. Such MDR inhibitors include inhibitors of p-glycoprotein (P-gp), such as LY335979, XR9576, OC144-093, R101922, VX853 and PSC833 (valspodar).

A compound of the present invention may be employed in conjunction with anti-emetic agents to treat nausea or emesis, including acute, delayed, late-phase, and anticipatory emesis, which may result from the use of a compound of the present invention, alone or with radiation therapy. For the prevention or treatment of emesis, a compound of the present invention may be used in conjunction with other anti-emetic agents, especially neurokinin-1 receptor antagonists, 5HT3 receptor antagonists, such as ondansetron, granisetron, tropisetron, and zatisetron, GABAB receptor agonists, such as baclofen, a corticosteroid such as Decadron (dexamethasone), Kenalog, Aristocort, Nasalide, Preferid, Benecorten or others such as disclosed in U.S. Pat. Nos. 2,789,118, 2,990,401, 3,048,581, 3,126,375, 3,929,768, 3,996,359, 3,928,326 and 3,749,712, an antidopaminergic, such as the phenothiazines (for example prochlorperazine, fluphenazine, thioridazine and mesoridazine), metoclopramide or dronabinol. In another embodiment, conjunctive therapy with an anti-emesis agent selected from a neurokinin-1 receptor antagonist, a 5HT3 receptor antagonist and a corticosteroid is disclosed for the treatment or prevention of emesis that may result upon administration of the instant compounds.

Neurokinin-1 receptor antagonists of use in conjunction with the compounds of the present invention are fully described, for example, in U.S. Pat. Nos. 5,162,339, 5,232,929, 5,242,930, 5,373,003, 5,387,595, 5,459,270, 5,494,926, 5,496,833, 5,637,699, 5,719,147; European Patent Publication Nos. EP 0 360 390, 0 394 989, 0 428 434, 0 429 366, 0 430 771, 0 436 334, 0 443 132, 0 482 539, 0 498 069, 0 499 313, 0 512 901, 0 512 902, 0 514 273, 0 514 274, 0 514 275, 0 514 276, 0 515 681, 0 517 589, 0 520 555, 0 522 808, 0 528 495, 0 532 456, 0 533 280, 0 536 817, 0 545 478, 0 558 156, 0 577 394, 0 585 913, 0 590 152, 0 599 538, 0 610 793, 0 634 402, 0 686 629, 0 693 489, 0 694 535, 0 699 655, 0 699 674, 0 707 006, 0 708 101, 0 709 375, 0 709 376, 0 714 891, 0 723 959, 0 733 632 and 0 776 893; PCT International Patent Publication Nos. WO 90/05525, 90/05729, 91/09844, 91/18899, 92/01688, 92/06079, 92/12151, 92/15585, 92/17449, 92/20661, 92/20676, 92/21677, 92/22569, 93/00330, 93/00331, 93/01159, 93/01165, 93/01169, 93/01170, 93/06099, 93/09116, 93/10073, 93/14084, 93/14113, 93/18023, 93/19064, 93/21155, 93/21181, 93/23380, 93/24465, 94/00440, 94/01402, 94/02461, 94/02595, 94/03429, 94/03445, 94/04494, 94/04496, 94/05625, 94/07843, 94/08997, 94/10165, 94/10167, 94/10168, 94/10170, 94/11368, 94/13639, 94/13663, 94/14767, 94/15903, 94/19320, 94/19323, 94/20500, 94/26735, 94/26740, 94/29309, 95/02595, 95/04040, 95/04042, 95/06645, 95/07886, 95/07908, 95/08549, 95/11880, 95/14017, 95/15311, 95/16679, 95/17382, 95/18124, 95/18129, 95/19344, 95/20575, 95/21819, 95/22525, 95/23798, 95/26338, 95/28418, 95/30674, 95/30687, 95/33744, 96/05181, 96/05193, 96/05203, 96/06094, 96/07649, 96/10562, 96/16939, 96/18643, 96/20197, 96/21661, 96/29304, 96/29317, 96/29326, 96/29328, 96/31214, 96/32385, 96/37489, 97/01553, 97/01554, 97/03066, 97/08144, 97/14671, 97/17362, 97/18206, 97/19084, 97/19942 and 97/21702; and in British Patent Publication Nos. 2 266 529, 2 268 931, 2 269 170, 2 269 590, 2 271 774, 2 292 144, 2 293 168, 2 293 169, and 2 302 689. The preparation of such compounds is fully described in the aforementioned patents and publications, which are incorporated herein by reference.

In an embodiment, the neurokinin-1 receptor antagonist for use in conjunction with the compounds of the present invention is selected from: 2-(R)-(1-(R)-(3,5-bis(trifluoromethyl)phenyl)ethoxy)-3-(S)-(4-fluorophenyl)-4-(3-(5-oxo-1H,4H-1,2,4-triazolo)methyl)morpholine, or a pharmaceutically acceptable salt thereof, which is described in U.S. Pat. No. 5,719,147.

A compound of the instant invention may also be administered with an agent useful in the treatment of anemia. Such an anemia treatment agent is, for example, a continuous eythropoiesis receptor activator (such as epoetin alfa).

A compound of the instant invention may also be administered with an agent useful in the treatment of neutropenia. Such a neutropenia treatment agent is, for example, a hematopoietic growth factor which regulates the production and function of neutrophils such as a human granulocyte colony stimulating factor, (G-CSF). Examples of a G-CSF include filgrastim.

A compound of the instant invention may also be administered with an immunologic-enhancing drug, such as levamisole, isoprinosine and Zadaxin.

A compound of the instant invention may also be useful for treating or preventing cancer, including bone cancer, in combination with bisphosphonates (understood to include bisphosphonates, diphosphonates, bisphosphonic acids and diphosphonic acids). Examples of bisphosphonates include but are not limited to: etidronate (Didronel), pamidronate (Aredia), alendronate (Fosamax), risedronate (Actonel), zoledronate (Zometa), ibandronate (Boniva), incadronate or cimadronate, clodronate, EB-1053, minodronate, neridronate, piridronate and tiludronate including any and all pharmaceutically acceptable salts, derivatives, hydrates and mixtures thereof

A compound of the instant invention may also be useful for treating or preventing breast cancer in combination with aromatase inhibitors. Examples of aromatase inhibitors include but are not limited to: anastrozole, letrozole and exemestane.

A compound of the instant invention may also be useful for treating or preventing cancer in combination with siRNA therapeutics.

The compounds of the instant invention may also be administered in combination with γ-secretase inhibitors and/or inhibitors of NOTCH signaling. Such inhibitors include compounds described in WO 01/90084, WO 02/30912, WO 01/70677, WO 03/013506, WO 02/36555, WO 03/093252, WO 03/093264, WO 03/093251, WO 03/093253, WO 2004/039800, WO 2004/039370, WO 2005/030731, WO 2005/014553, U.S. Ser. No. 10/957,251, WO 2004/089911, WO 02/081435, WO 02/081433, WO 03/018543, WO 2004/031137, WO 20041031139, WO 2004/031138, WO 2004/101538, WO 2004/101539 and WO 02/47671 (including LY450139).

A compound of the instant invention may also be useful for treating or preventing cancer in combination with PARP inhibitors.

A compound of the instant invention may also be useful for treating cancer in combination with the following therapeutic agents: abarelix (Plenaxis Depot®); aldesleukin (Prokine®); Aldesleukin (Proleukin®); Aleemtuzimabb (Campath®); alitretinoin (Panretin®); alopurinol (Zyloprim®); altretamine (Hexalen®); amifostine (Ethyol®); anastrozole (Arimidex®); arsenic trioxide (Trisenox®); asparaginase (Elspar®); azacitidine (Vidaza®); bevacuzimab (Avastin®); bexarotene capsules (Targretin®); bexarotene gel (Targretin®); bleomycin (Blenoxane®); bortezomib (Velcade®); busulifan intravenous (Busulfex®); busulfan oral (Myleran®); calusterone (Methosarb®); capecitabine (Xeloda®); carboplatin (Paraplatin®); carmustine (BCNU®, BiCNU®); carmustine (Gliadel®); carmustine with Polifeprosan 20 Implant (Gliadel Wafer®); celecoxib (Celebrex®); cetuximab (Erbitux®); chlorambucil (Leukeran®); cisplatin (Platinol®); cladribine (Leustatin®, 2-CdA®); clofarabine (Clolar®); cyclophosphamide (Cytoxan®, Neosar®); cyclophosphamide (Cytoxan Injection®); cyclophosphamide (Cytoxan Tablet®); cytarabine (Cytosar-U®); cytarabine liposomal (DepoCyt®); dacarbazine (DTIC-Dome®); dactinomycin, actinomycin D (Cosmegen®); Darbepoetin alfa (Aranesp®); daunorubicin liposomal (DanuoXome®); daunorubicin, daunomycin (Daunorubicin®); daunorubicin, daunomycin (Cerubidine®); Denileukin diftitox (Ontak®); dexrazoxane (Zinecard®); docetaxel (Taxotere®); doxorubicin (Adriamycin PFS®); doxorubicin (Adriamycin®, Rubex®); doxorubicin (Adriamycin PFS Injection®); doxorubicin liposomal (Doxil®); DROMOSTANOLONE PROPIONATE (DROMOSTANOLONE(D); DROMOSTANOLONE PROPIONATE (MASTERONE INJECTION®); Elliott's B Solution (Elliott's B Solution®); epirubicin (Ellence®); Epoetin alfa (Epogen®); erlotinib (Tarceva®); estramustine (Emcyt®); etoposide phosphate (Etopophos®); etoposide, VP-16 (Vepesid®); exemestane (Aromasin®); Filgrastim (Neupogen®); floxuridine (intraarterial) (FUDR®); fludarabine (Fludara®); fluorouracil, 5-FU (Adrucil®); fulvestrant (Faslodex®); gefitinib (Iressa®); gemcitabine (Gemzar®); gemtuzumab ozogamicin (Mylotarg®); goserelin acetate (Zoladex Implant®); goserelin acetate (Zoladex®); histrelin acetate (Histrelin Implant®); hydroxyurea (Hydrea®); Ibritumoomab Tiuxetan (Zevalin®); idarubicin (Idamycin®); ifosfamide (IFEX®); imatinib mesylate (Gleevec®); interferon alfa 2a (Roferon A®); Interferon alfa-2b (Intron A®); irinotecan (Camptosar®); lenalidomide (Revlimid®); letrozole (Femara®); leucovorin (Wellcovorin®, Leucovorin®); Leuprolide Acetate (Eligard®); levamisole (Ergamisol®); lomustine, CCNU (CeeBU®); meclorethamine, nitrogen mustard (Mustargen®); megestrol acetate (Megace®); melphalan, L-PAM (Alkeran®); mercaptopurine, 6-MP (Purinethol®); mesna (Mesnex®); mesna (Mesnex Tabs®); methotrexate (Methotrexate®); methoxsalen (Uvadex®); mitomycin C (Mutamycin®); mitotane (Lysodren®); mitoxantrone (Novantrone®); nandrolone phenpropionate (Durabolin-50®); nelarabine (Arranon®); Nofetumnomrab (Verluma®); Oprelvekin (Neurnega®); oxaliplatin (Eloxatin®); paclitaxel (Paxene®); paclitaxel (Taxol®); paclitaxel protein-bound particles (Abraxane®); palifermin (Kepivance®); pamidronate (Aredia®); pegademase (Adagen (Pegademase Bovine)®); pegaspargase (Oncaspar®); Pegfilgrastim (Neulasta®); pemetrexed disodium (Alimta®); pentostatin (Nipent®); pipobroman (Vercyte®); plicamycin, mithramycin (Mithracin®); porfimer sodium (Photofrin®); procarbazine (Matulane®); quinacrine (Atabrine®); Rasburicase (Elitek®); Rituximab (Rituxan®); sargramostim (Leukine®); Sargramostim (Prokine®); sorafenib (Nexavar®); streptozocin (Zanosar®); sunitinib maleate (Sutent®); talc (Scierosol®); tamoxifen (Nolvadex®); temozolomide (Temodar®); teniposide, VM-26 (Vumon®) testolactone (Teslac®); thioguanine, 6-TG (Thioguanine®); thiotepa (Thioplex®); topotecan (Hycamtin®); toremifene (Fareston®); Tositumomab (Bexxar®); Tositumomab/I-131 tositumomab (Bexxar®); Trastuzumab (Herceptin®); tretinoin, ATRA (Vesanoid®); Uracil Mustard (Uracil Mustard Capsules®); valrubicin (Vaistar®); vinblastine (Velban®); vincristine (Oncovin®); vinorelbine (Navelbine®); and zoledronate (Zometa®).

Thus, the scope of the instant invention encompasses the use of the instantly claimed compounds in combination with a second compound selected from: an estrogen receptor modulator, an androgen receptor modulator, a retinoid receptor modulator, a cytotoxic/cytostatic agent, an antiproliferative agent, a prenyl-protein transferase inhibitor, an HMG-CoA reductase inhibitor, an HIV protease inhibitor, a reverse transcriptase inhibitor, an angiogenesis inhibitor, PPAR-γ agonists, PPAR-δ agonists, an inhibitor of inherent multidrug resistance, an anti-emetic agent, an agent useful in the treatment of anemia, an agent useful in the treatment of neutropenia, an immunologic-enhancing drug, an inhibitor of cell proliferation and survival signaling, a bisphosphonate, an aromatase inhibitor, an siRNA therapeutic, γ-secretase inhibitors, agents that interfere with receptor tyrosine kinases (RTKs), an agent that interferes with a cell cycle checkpoint and any of the therapeutic agents listed above.

The term “administration” and variants thereof (e.g., “administering” a compound) in reference to a compound of the invention means introducing the compound or a prodrug of the compound into the system of the animal in need of treatment. When a compound of the invention or prodrug thereof is provided in combination with one or more other active agents (e.g., a cytotoxic agent, etc.), “administration” and its variants are each understood to include concurrent and sequential introduction of the compound or prodrug thereof and other agents.

As used herein, the term “composition” is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts.

The term “therapeutically effective amount” as used herein means that amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue, system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician.

The term “treating cancer” or “treatment of cancer” refers to administration to a mammal afflicted with a cancerous condition and refers to an effect that alleviates the cancerous condition by killing the cancerous cells, but also to an effect that results in the inhibition of growth and/or metastasis of the cancer.

In an embodiment, the angiogenesis inhibitor to be used as the second compound is selected from a tyrosine kinase inhibitor, an inhibitor of epidermal-derived growth factor, an inhibitor of fibroblast-derived growth factor, an inhibitor of platelet derived growth factor, an MMP (matrix metalloprotease) inhibitor, an integrin blocker, interferon-α, interleukin-12, pentosan polysulfate, a cyclooxygenase inhibitor, carboxyamidotriazole, combretastatin A-4, squalamine, 6-O-chloroacetyl-carbonyl)-fumagillol, thalidomide, angiostatin, troponin-1, or an antibody to VEGF. In an embodiment, the estrogen receptor modulator is tamoxifen or raloxifene.

Also included in the scope of the claims is a method of treating cancer that comprises administering a therapeutically effective amount of a compound of the instant invention in combination with radiation therapy and/or in combination with a second compound selected from: an estrogen receptor modulator, an androgen receptor modulator, a retinoid receptor modulator, a cytotoxiccytostatic agent, an antiproliferative agent, a prenyl-protein transferase inhibitor, an HMG-CoA reductase inhibitor, an HIV protease inhibitor, a reverse transcriptase inhibitor, an angiogenesis inhibitor, PPAR-γ agonists, PPAR-δ agonists, an inhibitor of inherent multidrug resistance, an anti-emetic agent, an agent useful in the treatment of anemia, an agent useful in the treatment of neutropenia, an immunologic-enhancing drug, an inhibitor of cell proliferation and survival signaling, a bisphosphonate, an aromatase inhibitor, an siRNA therapeutic, γ-secretase inhibitors, agents that interfere with receptor tyrosine kinases (RTKs), an agent that interferes with a cell cycle checkpoint and any of the therapeutic agents listed above.

And yet another embodiment of the invention is a method of treating cancer that comprises administering a therapeutically effective amount of a compound of the instant invention in combination with paclitaxel or trastuzumab.

The invention further encompasses a method of treating or preventing cancer that comprises administering a therapeutically effective amount of a compound of the instant invention in combination with a COX-2 inhibitor.

The instant invention also includes a pharmaceutical composition useful for treating or preventing cancer that comprises a therapeutically effective amount of a compound of the instant invention and a second compound selected from: an estrogen receptor modulator, an androgen receptor modulator, a retinoid receptor modulator, a cytotoxic/cytostatic agent, an antiproliferative agent, a prenyl-protein transferase inhibitor, an HMG-CoA reductase inhibitor, an HIV protease inhibitor, a reverse transcriptase inhibitor, an angiogenesis inhibitor, a PPAR-γ agonist, a PPAR-δ agonist, an inhibitor of cell proliferation and survival signaling, a bisphosphonate, an aromatase inhibitor, an siRNA therapeutic, γ-secretase inhibitors, agents that interfere with receptor tyrosine kinases (RTKs), an agent that interferes with a cell cycle checkpoint and any of the therapeutic agents listed above.

All patents, publications and pending patent applications identified are hereby incorporated by reference.

Abbreviations used in the description of the chemistry and in the Examples that follow are: AEBSF (p-aminoethylbenzenesulfonyl fluoride); Boc₂O (di-tert-butyl dicarbonate); BSA (bovine serum albumin); BuLi (n-Butyl lithium); CDCl₃ (chloroform-d); CuI (copper iodide); CuSO₄ (copper sulfate); DCE (dichloroethane); DCM (dichloromethane); DEAD (diethyl azodicarboxylate); DMAP (4-aminopyridine); DMF (N,N-dimethylformamide); DMSO (dimethyl sulfoxide); DTT (dithiothreitol); EDTA (ethylene-diamine-tetra-acetic acid); EGTA (ethylene-glycol-tetra-acetic acid); EtOAc (ethyl acetate); EtOH (ethanol); HOAc (acetic acid); HPLC (high-performance liquid chromatography); HRMS (high resolution mass spectrum); LCMS (liquid chromatograph-mass spectrometer); LHMDS (lithium bis(trimethylsilyl)amide); LRMS (low resolution mass spectrum); MeOH (methanol); MP-B(CN)H₃ (Macroporous cyanoborohydride); NaHCO₃ (sodium bicarbonate); Na₂SO₄ (sodium sulfate); Na(OAc)₃BH (sodium triacetoxyborohydride); NH₄OAc (ammonium acetate); NBS (N-bromosuccinamide); NMP (1-methyl-2-pyrrolidinone); NMR (nuclear magnetic resonance); PBS (phosphate buffered saline); PCR (polymerase chain reaction); Pd(dppf) ([1,1′-bis(diphenylphosphino)ferrocene]palladium); Pd(Ph₃)₄ (palladium(0) tetrakis-triphenylphosphine); POCl₃ (phosphorous oxychloride); PS-DIEA (polystyrene diisopropylethylamine); PS—PPh₃ (polystyrene-triphenyl phosphine); PTSA (para-toluene sulfonic acid); RaNi (Raney-Nickel); Selectfluor (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate); TBAF (tetrabutylammonium fluoride); THF (tetrahydrofuran); TFA (trifluoroacteic acid); and TMSCH₂N₂ (trimethylsilyldiazomethane).

The compounds of this invention may be prepared by employing reactions as shown in the following Reaction Scheme, in addition to other standard manipulations that are known in the literature or exemplified in the experimental procedures. The illustrative Reaction Scheme below, therefore, is not limited by the compounds listed or by any particular substituents employed for illustrative purposes. Substituent numbering as shown in the Reaction Scheme does not necessarily correlate to that used in the claims and often, for clarity, a single substituent is shown attached to the compound where multiple substituents are optionally allowed under the definitions of Formula A hereinabove.

Reactions used to generate the compounds of this invention are prepared by employing reactions as shown in Reaction Scheme I.

Synopsis of Reaction Scheme

As shown in Reaction Scheme I, the aminobenzoic acid can be cyclized with ethylchloroacetate to provide benzoxazinone (A-1). This latent electrophile can be reacted with the sodium anion of methyl acetoacetate to provide acrylate A-2. Upon treatment of sodium methoxide, A-2 can be internally cyclized and decarboxylated to provide the 4-hydroxyquinolinone A-3. Under microwave heating, the pyrazoloquinolinone (A-4) can be formed from hydrazine and catalytic acid. Selective benzyl protection can occur on the pyrazole nitrogen to give N-benzylated-pyrazoloquinolinone (A-5) which can allow for alkylation by a variety of bromides in the presence of cesium carbonate to give the N-alkylated compounds (A-6). The benzyl group can then be removed by hydrogenation using palladium on carbon to provide A-7. BOC group deprotection of alkyl amines with HCl can give the fully elaborated pyrazoloquinolinone (A-8).

EXAMPLES

Examples provided are intended to assist in a further understanding of the invention. Particular materials employed, species and conditions are intended to be further illustrative of the invention and not limitative of the reasonable scope thereof. The reagents utilized in synthesizing the compounds depicted are either commercially available or are readily prepared by one of ordinary skill in the art.

3-amino-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid (1-2)

To a mixture of activated Raney Nickel (200 g of 50% slurry in water on aluminum; 700 mmol, 13 equiv) and 3-amino-2-naphthoic acid (1-1) (10 g, 53 mmol, 1 equiv) in 1:1 isopropanol:water (400 mL) at 90° C. was added 1% aqueous NaOH solution (200 mL) over 1 h. The reaction mixture was stirred for 16 h at 90° C. and additional Raney Nickel (50 g, 180 mmol, 3.4 equiv) was added and the resulting mixture was heated at 90° C. for 24 h. The mixture was filtered and the filtrate was concentrated to 200 mL of water and brought to pH=3 with the addition of 1N aqueous hydrochloric acid solution to precipitate the product. The off-white precipitate was filtered, and purified by reverse phase liquid chromatography (H₂O/CH₃CN gradient w/0.1% TFA present) to yield 3-amino-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid (1-2) as a white solid. LRMS m/z (M+H) 192.2 found, 192.1 required.

2-ethoxy-6,7,8,9-tetrahydro-4H-naphtho[2,3-d][1,3]oxazin-4-one (1-3)

To a solution of 3-amino-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid (1-2) (5.0 g, 26 mmol, 1 equiv) in pyridine (50 mL) at −10° C. under nitrogen was added ethyl chloroformate (10 mL, 11 g, 100 mmol, 4.0 equiv) dropwise over 1 h. The resulting solution was stirred from −10° C. to 23° C. over 20 h. The solvent was evaporated under reduced pressure and the solid residue was suspended in water (100 mL) with stirring for 1 h. The precipitate was filtered, washed with water and dried to yield 2-ethoxy-6,7,8,9-tetrahydro-4H-naphtho[2,3-d][1,3]oxazin-4-one (1-3) as a yellow solid. LRMS m/z (M+H) 246.4 found, 246.1 required.

methyl (2Z)-2-acetyl-3-{3-[(ethoxycarbonyl)amino]-5,6,7,8-tetrahydronaphthalen-2-yl}-3-hydroxyorop-2-enoate (1-4)

To a dispersion of sodium hydride (95%) (0.80 g, 33 mmol, 2.1 equiv) in anhydrous benzene (100 mL) under nitrogen was added dropwise methyl acetoacetate (5.0 mL, 5.4 g, 46 mmol, 2.9 equiv) and the resulting mixture was stirred at 23° C. for 1 h. 2-ethoxy-6,7,8,9-tetrahydro-4H-naphtho[2,3-d][1,3]oxazin-4-one (1-3) (3.8 g, 16 mmol, 1 equiv) was added and the reaction mixture was stirred for 20 h. The excess sodium hydride was quenched with water and the organic layer was separated, extracted three times with water and the combined aqueous layers were made acidic with concentrated hydrochloric acid solution. The resulting precipitate was filtered and dried to yield methyl (2Z)-2-acetyl-3-{3-[(ethoxycarbonyl)amino]-5,6,7,8-tetrahydronaphthalen-2-yl}-3-hydroxyprop-2-enoate (1-4) as a yellow oil. LRMS m/z (M+H) 362.5 found, 362.2 required.

3-acetyl-4-hydroxy-6,7,8,9-tetrahydrobenzo[r]quinolin-2(1H)-one (1-5)

To a mixture of sodium hydride (95%) (0.70 g, 29 mmol, 2.6 equiv) in benzene (100 mL) at 23° C. under nitrogen was added methanol (2.5 mL, 2.0 g, 62 mmol, 5.4 equiv) dropwise over 10 min. After stirring for an additional 5 min, methyl (2Z)-2-acetyl-3-{3-[(ethoxycarbonyl)amino]-5,6,7,8-tetrahydronaphthalen-2-yl}-3-hydroxyprop-2-enoate (1-4) (4.1 g, 11 mmol, 1 equiv) was added and the resulting mixture was heated at 72° C. for 20 h. The solvent was evaporated under reduced pressure and the solid residue was suspended in water (50 mL) for 30 min followed by 1 N aqueous hydrochloric acid solution (100 mL) for an additional 30 min with stirring. The solid was filtered, washed with water (100 mL) and hexanes (100 mL), and dried to yield 3-acetyl-4-hydroxy-6,7,8,9-tetrahydrobenzo[g]quinolin-2(1H)-one (1-5) as an off-white solid. LRMS m/z (M+H) 258.4 found, 258.1 required.

3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-6)

A mixture of 3-acetyl-4-hydroxy-6,7,8,9-tetrahydrobenzo[g]quinolin-2(1H)-one (1-5) (2.0 g, 7.8 mmol, 1 equiv), hydrazine (0.40 mL, 0.41 g, 13 mmol, 1.6 equiv), and catalytic concentrated hydrochloric acid solution (2 drops) in DMA (30 mL) was heated at 140° C. under nitrogen for 16 h. The solution was cooled and diluted with water (30 mL). The precipitate was filtered, washed with hexanes (3×100 mL), and dried to yield 3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-6) as an off-white solid. ¹H NMR (500 MHz, DMSO-d₆) δ 13.51 (s, 1H), 10.99 (s, 1H), 7.70 (s, 1H) 7.04 (s, 1H), 2.78 (m, 4H), 2.59 (s, 3H), 1.76 (m, 4H). LRMS m/z (M+H) 254.4 found, 254.1 required.

2-benzyl-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-7)

To a mixture of 3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-6) (10.2 g, 40.3 mmol, 1 equiv) and potassium carbonate (30.0 g, 217 mmol, 5.38 equiv) in DMF (100 mL) under nitrogen was added benzyl bromide (35.0 g, 205 mmol, 5.09 equiv) and the resulting mixture was stirred at 23° C. for 16 h. The reaction mixture was filtered and the filtered solid was washed with ether (3×200 mL) followed by water (3×250 mL) and dried to yield 2-benzyl-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-7) as a white solid. LRMS m/z (M+H) 344.2 found, 344.2 required.

tert-butyl 3-bromo-2-fluoropropylcarbamate (1-9)

To a suspension of NBS (20 g, 110 mmol, 3.0 equiv) in dichloromethane (250 mL) was added dropwise triphenylphosphine (28 g, 110 nmol, 3.0 equiv) in dichloromethane (100 mL). After addition was complete, the reaction mixture was stirred for 10 min and a solution of tert-butyl 2-fluoro-3-hydroxypropylcarbamate (1-8) (7.0 g, 36 mmol, 1 equiv) in dichloromethane (100 mL) followed by pyridine (3.5 g, 44 mmol, 1.2 equiv) were added. The resulting mixture was stirred at 23° C. under nitrogen for 16 h. The reaction solution was concentrated and purified by silica gel chromatography (100% hexanes to 100% ethyl acetate over 1 h, analysis by Ninhydrin stain) to yield tert-butyl 3-bromo-2-fluoropropylcarbamate (1-9) as a clear oil. ¹H NMR (500 MHz, CDCl₃) δ 4.89-4.68 (m, 2H), 3.55-3.40 (m, 2H), 1.45 (s, 9H).

tert-butyl 3-(2-benzyl-3-methyl-4-oxo-2,4,7,8,9,10-hexahydro-5H-benzo[g]pyrazolo[4,3-c]quinolin-5-yl)-2-fluorogropylcarbamate (1-10)

To a mixture of 2-benzyl-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-7) (8.0 g, 23 mmol, 1 equiv) and cesium carbonate (37 g, 110 mmol, 4.9 equiv) in DMF (100 mL) was added tert-butyl 3-bromo-2-fluoropropylcarbamate (1-9) (7.1 g, 27.7 mmol, 1.2 equiv) and the resulting mixture was stirred at 40° C. for 16 h. The reaction mixture was filtered and the filtrate concentrated and purified by silica gel chromatography (100% hexanes to 100% ethyl acetate over 1 h) to yield tert-butyl 3-(2-benzyl-3-methyl-4-oxo-2,4,7,8,9,10-hexahydro-5H-benzo[g]pyrazolo[4,3-c]quinolin-5-yl)-2-fluoropropylcarbamate (1-10) as a white solid. LRMS m/z (M+H) 519.2 found, 519.3 required.

tert-butyl 2-fluoro-3-(3-methyl-4-oxo-2,4,7,8,9,10-hexahydro-5H-benzo[g]pyrazolo[4,3-c]quinolin-5-yl)propylcarbamate (1-11)

A mixture of tert-butyl 3-(2-benzyl-3-methyl-4-oxo-2,4,7,8,9,10-hexahydro-5H-benzo[g]pyrazolo[4,3-c]quinolin-5-yl)-2-fluoropropylcarbamate (1-10) (0.10 g, 0.19 mmol, 1 equiv) and 10% palladium on carbon (300 mg) in DMF (10 mL) and methanol (10 mL) was stirred under a hydrogen balloon at 23° C. for 72 h. The resulting suspension was filtered and the filtrate was concentrated to yield tert-butyl 2-fluoro-3-(3-methyl-4-oxo-2,4,7,8,9,10-hexahydro-5H-benzo[g]pyrazolo[4,3-c]quinolin-5-yl)propylcarbamate (1-11). LRMS m/z (M+H) 429.2 found, 429.2 required.

tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-c]quinoline-2-carboxylate (1-12)

To a solution of tert-butyl 2-fluoro-3-(3-methyl-4-oxo-2,4,7,8,9,10-hexahydro-5H-benzo[g]pyrazolo[4,3-]quinolin-5-yl)propylcarbamate (1-11) (0.083 g, 0.19 mmol, 1 equiv) and Boc₂O (0.05 g, 0.23 mmol, 1.2 equiv) in DMF (10 mL) was added DMAP (0.005 g, 0.04 mmol, 0.2 equiv) and the resulting solution was stirred at 23° C. for 3 h. The solution was concentrated and the residue purified by silica gel chromatography (100% hexanes to 100% ethyl acetate over 1 h) to yield tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-c]quinoline-2-carboxylate (1-12) as a white solid. LRMS m/z (M+H) 529.3 found, 529.3 required.

To a solution of a racemic mixture of tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-c]quinoline-2-carboxylate (1-12, 130 mg, 0.246 mmol) in methanol (10 mL) was added 4 N HCl solution in dioxane (10 mL) and the resulting solution was stirred at 23° C. for 16 h. The clear gel precipitate was filtered, and the filtered solid was washed with ethyl acetate, dissolved in water and concentrated to yield the hydrochloride salt of a racemic mixture of 5-(3-amino-2-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one as a white solid (1-12a). ¹H NMR (500 MHz, CD₃OD) δ 7.76 (s, 1H), 7.39 (s, 1H), 5.20 (m, 1H), 4.66 (m, 2H), 3.46 (m, 2H), 2.94 (m, 4H), 2.71 (s, 3H), 1.87 (m, 4H). LRMS m/z (M+H) 329.2 found, 329.2 required.

tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-(R)-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-c]quinoline-2-carboxylate (1-13) and (2-S)-tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-(S)-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-c]quinoline-2-carboxylate (1-14)

A racemic mixture of tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-c]quinoline-2-carboxylate (1-12) was resolved into its constituent enantiomers using a Chiralcel OD (5 cm×50 cm, 201) prep column with an 80% hexane/20% isopropanol gradient at 90 mL/min to give tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-(R)-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-]quinoline-2-carboxylate (1-13) and (2-S)-tert-butyl 5-{3-[(tert-butoxycarbonyl)amino]-2-(S)-fluoropropyl}-3-methyl-4-oxo-4,5,7,8,9,10-hexahydro-2H-benzo[g]pyrazolo[4,3-]quinoline-2-carboxylate (1-14) as white solids. LRMS m/z (M+H) 529.3 found, 529.3 required.

5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-15) and 5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-16)

To separate solutions of 5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-13) (0.60 g, 1.1 mmol, 1 equiv) and 5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-14) (0.70 g, 13 mmol, 1 equiv) in methanol (20 mL) was added 4 N HCl solution in dioxane (30 mL) and the resulting solutions were stirred at 40° C. for 16 h. The clear gel precipitate was filtered, and the filtered solid was washed with ethyl acetate, dissolved in water and concentrated to yield the hydrochloride salts of 5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-15) and 5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-16) as white solids. ¹H NMR (500 MHz, CD₃OD) δ 7.76 (s, 1H), 7.39 (s, 1H), 5.20 (m, 1H), 4.66 (m, 2H), 3.46 (m, 2H), 2.94 (m, 4H), 2.71 (s, 3H), 1.87 (m, 4H). LRMS m/z (M+H) 329.2 found, 329.2 required.

5-(3-amino-2,2-difluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one (1-17) was prepared using 3-[(tert-butoxycarbonyl)amino]-2,2-difluoropropyl trifluoromethanesulfonate as the alkylating agent by the methods described above.

1-17

5-(3-amino-2,2-difluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one LRMS m/zz(M + H)347.2 found,347.2required.

Examples 1-9

Examples are provided below to further illustrate different features and advantages of the present invention. The examples also illustrate useful methodology for practicing the invention. These examples do not limit the claimed invention.

Example 1 Identification of CHK1sv1 Using Real-Time PCR

To facilitate the determination of compound inhibitory properties, it is desirable to identify variants of the “normal” splicing of exon regions encoding CHK1. In particular, naturally occurring splicing variations resulting in the loss of the C-terminal regulatory domain of CHK1 were sought. Deletion of the C-terminus confers greater kinase activity to CHK1 (Chen et al., 2000, Cell 100:681-692; Katsuragi and Sagata, 2004, Mol. Biol. Cell. 15:1680-1689). Exons 2-8 encode the catalytic kinase domain and exon 9 encodes the linker region. The SQ and C-terminal regulatory domains lie within exons 10-13 (Sanchez et al., 1997, 277:1497-1501; Katsuragi and Sagata, 2004, Mol. Biol. Cell. 15:1680-1689). Real-time PCR experiments and RT-PCR have been used to identify and confirm the presence of novel splice variants of human CHK1 mRNA. A naturally occurring splice variant which encodes a C-terminal truncation of the CHK1 inhibitory domain was identified, cloned, expressed and purified for use in a CHK1 kinase assay of utility for the determination of compound inhibitory properties.

RT-PCR

The structure of CHK1 mRNA in the region corresponding to exons 8 to 11 was determined for RNA extracted from human testis using an RT-PCR based assay. Total RNA isolated from human testis was obtained from BD Biosciences Clontech (Palo Alto, Calif.). RT-PCR primers were selected that were complementary to sequences in exon 8 and exon 11 of the reference exon coding sequences in CHK1 (NM_(—)001274). Based upon the nucleotide sequence of CHK1 mRNA, the CHK1 exon 8 and exon 11 primer set (hereafter CHK1₈₋₁₁ primer set) was expected to amplify a 478 base pair amplicon representing the “reference” CHK1 RNA region. The CHK1₈₋₁₁ primer set was expected to amplify a 300 base pair amplicon in a transcript that possessed alternative splicing of exon 9 to exon 11. The CHK1 exon 8 forward primer has the sequence: 5′ ATCAGCAAGAATTACCATTCCAGACATC 3′ (SEQ ID NO 1); and the CHK1 exon 11 reverse primer has the sequence: 5′ CATACAACTTTTCTTCCATTGATAGCCC 3′ (SEQ ID NO 2).

Total RNA from human testis was subjected to a one-step reverse transcription-PCR amplification protocol using the Qiagen, Inc. (Valencia, Calif.), One-Step RT-PCR kit, using the following cycling conditions:

1) 50° C. for 30 minutes;

2) 95° C. for 15 minutes;

3) 35 cycles of:

-   -   94° C. for 30 seconds;     -   63.5° C. for 40 seconds;     -   72° C. for 50 seconds; then     -   72° C. for 10 minutes.

RT-PCR amplification products (amplicons) were size fractionated on a 2% agarose gel. Selected fragments representing 250 to 350 base pair amplicons were manually extracted from the gel and purified with a Qiagen Gel Extraction Kit. The purified amplicon fragments were reamplified with the CHK1₈₋₁₁ primer set, and these amplicons were size fractionated on an agarose gel. Fragments representing 250 to 350 base pair amplicons were manually extracted from the gel and purified with a Qiagen Gel Extraction Kit. The purified amplicon fragments were reamplified with the CHK1₈₋₁₁ primer set once more. Following size fractionation on an agarose gel and manual extraction of the 250 to 350 base pair amplicons, the purified amplicon fragments (Qiagen Gel Extraction Kit) were cloned into an Invitrogen pCR2.1 vector using the reagents and instructions provided with the TOPO TA cloning kit (Invitrogen, Carlsbad, Calif.). Clones were then plated in pools of 440 colonies per plate, onto 15 plates, for a total of 6600 clones. DNA was extracted from the pooled 440 colonies from each plate and used as template for real-time PCR.

Real-Time PCR/TAQman

To determine the presence of an alternatively spliced isoform to the CHK1 reference protein (NP_(—)001265), a real-time PCR assay was used.

TAQman primers and probes used to detect the CHK1sv1 isoform were designed and synthesized as pre-set mixtures (Applied Biosystems, Foster City, Calif.). The sequences of the TAQman primers and probes used to detect the CHK1 reference form (SEQ ID NOs 3, 4, and 5) and CHK1sv1 isoform (SEQ ID NOs 6, 7, and 8) are shown in Table 1. Splice junction specific probes were labeled with the 6-FAM fluorophore at the 5′ end (FAM) and a non-fluorescent quencher at the 3′ end (NFQ). Real-time PCR was performed on human testis cDNA using the TaqMan Universal PCR Master Mix (Applied Biosystems, Foster City, Calif.). The TAQman reaction contained:

96-well format 384-well format 12.5 μl   5 μl TAQman Universal MasterMix 1.25 μl 0.5 μl Primer-probe mix 6.25 μl 2.5 μl H₂O   5 μl   2 μl DNA

TABLE 1 Primers and probes used to detect CHK1 isoforms. Name SEQ ID NO Sequence Specificity CHK1 reference forward SEQ ID NO 3 GTTACTTGGCACCCCAGGA CHK1 primer reference CHK1 reference reverse SEQ ID NO 4 CATCCAATTTGGTAAAGAATCGTGTCA CHK1 primer reference CHK1 reference probe SEQ ID NO 5 FAM-TCCTCACAGAACCCC-NFQ CHK1 reference CHK1sv1 forward SEQ ID NO 6 GCACATTCAATCCAATTTGGACTTCT CHK1sv1 primer CHK1sv1 reverse primer SEQ ID NO 7 CATCCAATTTGGTAAAGAATCGTGTCAT CHK1sv1 CHK1sv1 probe SEQ ID NO 8 FAM-CAGTGCTTCTAGAACCC-NFQ CHK1sv1

The TAQman reactions were performed on an ABI Prism 7900HT Sequence Detection System (Applied Biosystems, Foster City, Calif.). The thermocycling conditions were 50° C. for 2 minutes, 95° C. for 10 minutes, and 40 cycles of 95° C. for 15 seconds and 60° C. for 1 minute. Data analysis of the fluorescence emission was performed by the Sequence Detector Software (SDS) (Applied Biosystems, Foster City, Calif.).

Results of the TAQman assay indicated that pooled DNA from 13 out of 15 plates appeared to possess clones that represented an alternative exon 9 to exon 11 splice junction. DNA from one of these positive pools, representing 440 colonies, was used to transform bacterial host cells. Clones were plated in pools of 55 colonies per plate onto 12 plates total. The colonies on each of the 12 plates were again pooled and used for a TAQman assay. Pooled DNA from 1 out of 12 plates appeared to possess a clone that represented an alternative exon 9 to exon 11 splice junction. The 55 colonies on this positive plate were individually screened using a TAQman assay, and one clone was identified as possessing an alternative exon 9 to exon 11 splice junction. This positive clone was then sequenced from each end using the CHK1 exon 8 forward primer (SEQ ID NO 1) and a different exon 11 reverse primer with the sequence 5′ TGCATCCAATTTGGTAAAGAATCG 3′ (SEQ ID NO 9).

Sequence analysis of the clone revealed that it matched the expected sequence for alternative splicing of exon 9 of the CHK1 heteronuclear RNA to exon 11; that is the coding sequence of exon 10 is completely absent.

Example 2 Cloning of CHK1sv1

Real-time PCR, RT-PCR, and sequencing data indicate that in addition to the normal CHK1 reference mRNA sequence, NM_(—)001274, encoding CHK1 protein, NP_(—)001265, a novel splice variant form of CHK1 mRNA also exist in testis tissue and MOLT-4, and Daudi cell lines.

Clones having a nucleotide sequence comprising the CHK1sv1 splice variant identified in Example 1 were isolated using recombination-mediated plasmid construction in yeast. A set of two primer pairs was used to amplify and clone the entire mRNA coding sequences of CHK1sv1. In the case of CHK1sv1, real-time quantitative PCR analysis indicated that transcripts of this splice variant form were present at very low levels. In order to clone CHK1sv1, clones containing coding sequences of the reference CHK1 (NM_(—)001274) were altered by an additional recombination step in yeast with 80 base pair linkers that were designed to create the desired exon 9 to exon 11 splice junction.

A 5′ “forward” primer and a 3′ “reverse” primer were designed for isolation of full length clones corresponding to CHK1sv1. The 5′ “forward” CHK1sv1 primer was designed to have the nucleotide sequence of 5′ TTACTGGCTTATCGAAATTAATACGACTCACTATAG GGAGGAGTCATGGCAGTGCCCTTTGT 3′ (SEQ ID NO 10) and to have sequences complementary to exon 2 of the CHK1 mRNA (NM_(—)001274). The 3′ “reverse” CHK1sv1 primer was designed to have the nucleotide sequence of 5′ TAGAAGGCACAGTCGAGGCTGA TCAGCGGGTTTAAACTCATGCATCCAATTTGGTAAAGAATCG 3′ (SEQ ID NO 11) and to have sequences complementary to exon 11 of the CHK1 mRNA (NM_(—)001274). The 40 nucleotides at the 5′ ends of the primer sequences indicated in italics are “tails” that were incorporated into the PCR amplicons and facilitated subsequent plasmid recombination events in yeast. These CHK1sv1 “forward” and “reverse” primers were expected to amplify coding sequences of the reference CHK1 mRNA (NM_(—)001274), which was then used in a subsequent recombinational cloning step to create CHK1sv1-specific sequence.

RT-PCR

The CHK1sv1 cDNA sequence was cloned using a combination of reverse transcription (RT) and polymerase chain reaction (PCR). More specifically, about 25 ng of MOLT-4 cell line mRNA (BD Biosciences Clontech, Palo Alto, Calif.) was reverse transcribed using Superscript II (Gibco/Invitrogen, Carlsbad, Calif.) and oligo d(T) primer (RESGEN/Invitrogen, Huntsville, Ala.) according to the Superscript II manufacturer's instructions. For PCR, 1 μl of the completed RT reaction was added to 40 μl of water, 5 μl of 10× buffer, 1 μl of dNTPs and 1 μl of enzyme from a Clontech (Palo Alto, Calif.) Advantage 2 PCR kit. PCR was done in a Gene Amp PCR System 9700 (Applied Biosystems, Foster City, Calif.) using the CHK1sv1 “forward” and “reverse” primers for CHK1sv1 (SEQ ID NOs 10,11). After an initial 94° C. denaturation of 1 minute, 35 cycles of amplification were performed using a 30 second denaturation at 94° C. followed by a 40 second annealing at 63.5° C. and a 50 second synthesis at 72° C. The 35 cycles of PCR were followed by a 10 minute extension at 72° C. The 50 μl reaction was then chilled to 4° C. 10 μl of the resulting reaction product was run on a 1% agarose (Invitrogen, Ultra pure) gel stained with 0.3 μg/ml ethidium bromide (Fisher Biotech, Fair Lawn, N.J.). Nucleic acid bands in the gel were visualized and photographed on a UV light box to determine if the PCR had yielded products of the expected size, in the case of the CHK1 mRNA, a product of about 1243 base pairs. The remainder of the 50 μl PCR reactions from MOLT-4 cells was purified using the QIAquik Gel extraction Kit (Qiagen, Valencia, Calif.) following the QIAquik PCR Purification Protocol provided with the kit. About 50 μl of product obtained from the purification protocol was concentrated to about 6 μl by drying in a Speed Vac Plus (SC110A, from Savant, Holbrook, N.Y.) attached to a Universal Vacuum System 400 (also from Savant) for about 30 minutes on medium heat.

Cloning and Assembly of CHK1sv1 Full-Length Clones and Yeast Transformation

Assembly of the full length CHK1sv1 clone by homologous recombination cloning in yeast was performed using a cycloheximide-based counterselection scheme similar to that described previously by Raymond et al. (2002, Genome Res. 12:190-197).

Assembly of the full-length CHK1sv1 full length clone by homologous recombination between the 1243 base pair CHK1 amplicon, produced using the CHK1sv1 forward and reverse “tailed” primers described earlier, and the expression vector was performed by simultaneous transformation of these pieces into yeast cells. A subsequent recombination step with 80 base pair oligonucleotide linkers created the CHK1sv1 exon 9 to exon 11 splice junction. All yeast transformation steps described in subsequent paragraphs were performed by electroporation (Raymond et al., 2002 Genome Res. 12:190-197).

1 μg of the 1243 base pair CHK1 purified amplicon was cloned directly into 100 ng of SrfI-digested pCMR11 by cotransformation of 100 μl of yeast strain CMY1-5 (Mate URA3Δ, CYH2^(R)). Ura⁺, cycloheximide resistant colonies were selected on Ura-deficient media plates containing 1 μg/ml cycloheximide (Sigma, St. Louis, Mo.). Standard yeast media were used (Sherman, 1991, Methods Enzymol. 194:3-21). Total DNA from yeast cell culture containing the CHK1 clone was used to transform E. coli to chloramphenicol (Sigma, St. Louis, Mo.) resistance to prepare a large quantity of the recombinant plasmid as described in Hoffman and Winston (1987 Gene 57:267-72). The colonies were picked from the plates into 2 ml of 2×LB media. These liquid cultures were incubated overnight at 37° C. Plasmid DNA was extracted from these cultures using the Qiagen (Valencia, Calif.) Qiaquik Spin Miniprep kit.

TABLE 2 Composition of pCMR11 plasmid Nucleotide coordinates Functional description of sequence   1-6013 Copy-control ™ E. coli origin of replication from pCClFOS (Epicentre Technologies, Madison, WI). 6014-7884 Yeast URA3 gene, ARS4 autonomously replicating sequence and CEN6 centromere from pRS316 (Sikorski and Hieter, 1989). 7885-8825 Mammalian CMV promoter from InVitrogen (Carlsbad, CA) vector pcDNA3.1/myc-HIS A.   8826-10,774 Yeast CYH2 gene amplified from strain BY4709 (Brachmann et al. 1998) 10,775-10,782 Engineered SrfI restriction site. 10,783-13,556 Mammalian poly-adenylation sites, selectable markers, SV40 origin, etc. from pcDNA3.1/myc-HIS A. 13,557-13,596 DNA sequence from InVitrogen vector pENTR11. 13,597-14,561 pCMR11 - specific; chloramphenicol resistance gene from pCClFOS.

To construct the CHK1sv1 clone, 1 μg of 80 base pair linkers shown in Table 3 (SEQ ID NOs 12, 13) that spans the region of the alternative splicing of exon 9 to exon 11, and 100 ng of BamHI-digested CHK1/pCMR11 clone were used to cotransform 100 μl of a cycloheximide sensitive yeast strain. The overlapping DNA between the linkers and CHK1/pCMR11 clone dictates that most yeast transformants will possess the correctly assembled construct. Ura⁺, cycloheximide resistant colonies were selected for subsequent preparation and transformation of E. coli. Plasmid DNA extracted from E. coli was analyzed by restriction digest to confirm the presence of the alternative splicing of exon 9 to exon 11 in the CHK1sv1 clone. Eight CHK1sv1 clones were sequenced to confirm identity, and the clones possessing the appropriate sequences are used for protein expression in multiple systems.

TABLE 3 Linkers used to create exon 9 to exon 11 splice junction for CHK1sv1 clone SEQ ID NO Linker Sequence SEQ ID NO 12 AATCCAATTTGGACTTCTCTCCAGTAAACAGTGCTTC TAGAACCCCTGGCAGCGGTTGGTCAAAAGAATGACAC GATTCT SEQ ID NO 13 AGAATCGTGTCATTCTTTTGACCAACCGCTGCCAGGG GTTCTAGAAGCACTGTTTACTGGAGAGAAGTCCAAAT TGGATT

Summary of CHK1sv1 Polynucleotide

The polynucleotide coding sequence of CHK1sv1 mRNA (Seq ID NO 14) contains an open reading frame that encodes a CHK1sv1 protein (SEQ ID NO 15) similar to the reference CHK1 protein (NP_(—)001265), but lacking amino acids encoded by a 178 base pair region corresponding to exons 10 of the full length coding sequence of reference CHK1 mRNA (NM_(—)001274). The deletion of the 178 base pair region results in a shift of the protein translation reading frame in comparison to the reference CHK1 protein reading frame, creating a carboxy terminal peptide region that is unique to CHK1sv1 (italicized in Seq ID NO 15). The frameshift also creates a premature termination codon 29 nucleotides downstream of the exon 9/exon 11 splice junction. Therefore, the CHK1sv1 protein is missing an internal 59 amino acid region corresponding to the amino acid region encoded by exon 10 and is also lacking the amino acids encoded by the nucleotides downstream of the premature stop codon as compared to the reference CHK1 (NP_(—)001265). Exon 10 encodes the SQ/TQ domains of CHK1, and exons 11-13 encode the autoinhibitory region (Sanchez et al., 1997, Science 277:1497-1501; Katsuragi and Sagata, 2004, Mol. Biol. Cell. 15: 1680-1689). While deletion of the autoinhibitory region confers constitutive activity to the CHK1 kinase domain, when the SQ/TQ domains are also removed, CHK1 enzymatic activity decreases (Ng et al., 2004, J. Biol. Chem. 279:8808-8819).

TABLE 4 Nucleotide coding sequence and coded polypeptide for CHK1sv1 Seq ID ATGGCAGTGCCCTTTGTGGAAGACTGGGACTTGGTGCAAACCCT NO 14 GGGAGAAGGTGCCTATGGAGAAGTTCAACTTGCTGTGAATAGAG TAACTGAAGAAGCAGTCGCAGTGAAGATTGTAGATATGAAGCGT GCCGTAGACTGTCCAGAAAATATTAAGAAAGAGATCTGTATCAA TAAAATGCTAAATCATGAAAATGTAGTAAAATTCTATGGTCACA GGAGAGAAGGCAATATCCAATATTTATTTCTGGAGTACTGTAGT GGAGGAGAGCTTTTTGACAGAATAGAGCCAGACATAGGCATGCC TGAACCAGATGCTCAGAGATTCTTCCATCAACTCATGGCAGGGG TGGTTTATCTGCATGGTATTGGAATAACTCACAGGGATATTAAA CCAGAAAATCTTCTGTTGGATGAAAGGGATAACCTCAAAATCTC AGACTTTGGCTTGGCAACAGTATTTCGGTATAATAATCGTGAGC GTTTGTTGAACAAGATGTGTGGTACTTTACCATATGTTGCTCCA GAACTTCTGAAGAGAAGAGAATTTCATGCAGAACCAGTTGATGT TTGGTCCTGTGGAATAGTACTTACTGCAATGCTCGCTGGAGAAT TGCCATGGGACCAACCCAGTGACAGCTGTCAGGAGTATTCTGAC TGGAAAGAAAAAAAAACATACCTCAACCCTTGGAAAAAAATCGA TTCTGCTCCTCTAGCTCTGCTGCATAAAATCTTAGTTGAGAATC CATCAGCAAGAATTACCATTCCAGACATCAAAAAAGATAGATGG TACAACAAACCCCTCAAGAAAGGGGCAAAAAGGCCCCGAGTCAC TTGAGGTGGTGTGTCAGAGTCTCCCAGTGGATTTTCTAAGCACA TTCAATCCAATTTGGACTTCTCTCCAGTAAACAGTGCTTCTAGA ACCCCTGGCAGCGGTTGGTCAAAAGAATGA Seq ID MAVPFVEDWDLVQTLGEGAYGEVQLAVNRVTEEAVAVKIVDMKR NO 15 AVDCPENIKKEICINKMLNHENVVKFYGHRREGNIQYLFLEYCS GGELFDRIEPDIGMPEPDAQRFFHQLMAGVVYLHGIGITHRDIK PENLLLDERDNLKISDFGLATVFRYNNRERLLNKMCGTLPYVAP ELLKRREFHAEPVDVWSCGIVLTAMLAGELPWDQPSDSCQEYSD WKEKKTYLNPWKKIDSAPLALLHKILVENPSARITIPDIKKDRW YNKPLKKGAKRPRVTSGGVSESPSGFSKHIQSNLDFSPVNSAS

Example 3 Expression of CHK1sv1 Protein

The baculovirus gene expression vector system permits protein expression insect cells, which are inexpensive and easy to maintain. The proteins produced are of similar quality to that in mammalian cells (Miller, 1988, Biotechnology 10:457-465; Miller, 1989, Bioessays 11:91-95). Methods of protein expression using the baculovirus expression vectors in insect cells are known in the art and techniques are discussed in O'Reilly et al., Baculovirus Expression Vectors—A Laboratory Manual, W. H. Freeman and Co., New York, 1992 and Baculovirus Expression Vector System Instruction Manual, 6^(th) edition, Pharmingen, San Diego, 1999.

Cloning CHK1sv1 for Insect Cell Expression

To create a CHK1sv1/baculovirus transfer vector construct, the CHK1sv1/pCMR11 clone (see Example 2) was used as template for PCR to amplify the coding sequence of CHK1sv1 (SEQ ID NO 14) using the primers listed in Table 5 (SEQ ID NOs 16, 17). The primer represented by SEQ ID NO 16 contains an optimal translation initiation sequence immediately upstream of the ATG start codon and an upstream EcoRI restriction site that become incorporated into the amplicon. The primer represented by SEQ ID NO 17 contains sequence encoding six histidine residues C-terminal to the CHK1 sv1 coding sequence as well as an EagI restriction site that become incorporated into the CHK1sv1 amplicon. The CHK1sv1 amplicon was run on a 1% agarose gel. A selected amplicon fragment of the expected size, in the case of CHK1sv1, a product of about 994 base pairs, was manually extracted from the gel and purified with a Qiagen Gel Extraction Kit. The purified amplicon fragment was digested with EcoRI and EagI. The EcoRI/EagI-digested amplicon was ligated into the baculovirus transfer vector pVL1393 (Pharmingen, San Diego, Calif.) which had been digested with EcoRI and EagI and dephosphorylated with alkaline phosphatase. The CHK1sv1/pVL1393 construct was then transformed into E. coli strain DH5α. Plasmid DNA extracted from selected from ampicillin resistant colonies was sequenced to confirm identity, and the clones possessing the appropriate sequences were used for protein expression in insect cells.

TABLE 5 Primers used to clone CHK1sv1 into baculovirus transfer vector pVL1393 SEQ ID NO Primer Sequence SEQ ID NO 16 CCCGGAATTCACCATGGCAGTGCCCTTTGTGGAAGAC TGG SEQ ID NO 17 TGTGTCCGGCCGTCAGTGATGGTGATGGTGATGTTCT TTTGACCAACCGCTGCC

Insect Cell Expression of CHK1sv1

The CHK1sv1/pVL1393 construct was co-transfected with linearized AcNPV BaculoGold DNA (Pharmingen, San Diego, Calif.) into SF9 insect cells (Invitrogen, Carlsbad, Calif.). Individual recombinant viruses were selected by end point dilution. Virus clones were amplified to obtain high titer stocks. These virus stocks were used for protein expression tests in small scale SF9 cultures to verify production of the CHK1 sv1 recombinant protein. Transfected SF9 cell lysates were analyzed by polyacrylamide gel electrophoresis for CHK1sv1 protein expression. The CHK1sv1 protein was visualized by Commassie staining or by Western blotting using an anti-CHK1 antibody (G4 antibody; Santa Cruz Biotechnology, Inc). Based on expression, an individual virus was selected for larger scale CHK1sv1 expression. For recombinant protein expression on the liter scale, SF9 suspension cultures were grown at 27° C. in Ex-cell 401 serum-free media (JRH Scientific, Lenexa, Kans.) and were infected with a recombinant virus stock using a multiplicity of infection of 0.3 virus per cell. The infected SF9 culture was harvested 72 hour following virus transfection, and pelleted by centrifugation. Pellets were stored at −70° C.

Purification of CHK1sv1 Recombinant Protein

Insect cell pellets were lysed with B-PER protein extraction reagent (Pierce, Rockford, Ill.) containing 1 μM microcystin (Sigma, St. Louis, Mo.), 10 μM cypermethrin (EMD Biosciences, San Diego, Calif.), and EDTA-free Protease Inhibitor Cocktail (Roche Diagnostics, Mannheim, Germany) (I tablet/50 ml lysis buffer). All manipulations during protein purification were performed at 4° C. Cells were resuspended in the lysis buffer were stirred for 45 minutes. DNAseI (Roche) was then added to a final concentration of 200 U/ml and the cell suspension was stirred for an additional 30 minutes. The lysed cell suspension was centrifuged for 30 minutes at 30,000 g. The lysis supernatant was decanted and centrifuged for 30 minutes at 30,000 g. For each 10 ml of cleared supernatant, 1 ml bed volume of Talon metal affinity resin (Clontech, Palo Alto, Calif.) was added, and the suspension was stirred for 45 minutes. The affinity resin/lysate suspension was centrifuged at 5000 g for 3 minutes and then the supernatant was discarded. The affinity resin was washed 4× with Buffer A (50 μM Tris, pH 8.0; 250 mM NaCl) using 5× volumes of the resin. The washed resin was resuspended as a 2× slurry in Buffer A and packed into a chromatography column. The resin-packed column was washed with 6× bed volumes of Buffer A. CHK1sv1-His-tagged protein is eluted from the column using a step-wise gradient of imidazole in Buffer A. Imidazole concentrations in the 2× bed volume fractions were 5, 10, 20, 30, 40, 50, and 60 mM. Elution fractions were concentrated using the Amicon Ultra 15 Centrifugal Filter Device, 30,000 Nominal Molecular Weight Limit (Millipore, Billerica, Mass.). The concentrated enzyme fractions were diluted 50% in glycerol and stored at −20° C. Fractions were analyzed for the presence of CHK1sv1-His-tagged protein using polyacrylamide gel electrophoresis followed by Coomrmassie staining and Western blotting using an anti-CHK1 antibody (G4 antibody; Santa Cruz Biotechnology, Inc). The CHK1sv1 kinase activity of the column fractions was determined using the kinase assay described in the following section.

Example 4 CHK1sv1 Kinase Assay

CHK1sv1 activity was assayed in vitro using a synthetic peptide substrate. The phosphopeptide product was quantitated using a Homogenous Time-Resolved Fluorescence (HTRF) assay system (Park et al., 1999, Anal. Biochem. 269:94-104). The reaction mixture contained 40 mM HEPES, pH 7.3; 100 mM NaCl; 10 mM MgCl₂; 2 mM dithiothreitol; 0.1% BSA; 0.1 mM ATP; 0.5 μM peptide substrate; and 0.1 nM CHK1sv1 enzyme in a final volume of 40 μl. The peptide substrate has the amino acid sequence amino terminus-GGRARTSSFAEPG-carboxy terminus (Synpep, Dublin Calif.) (SEQ ID NO 18) and is biotinylated at the N-terminus. The kinase reaction was incubated for 30 minutes at 22° C., and then terminated with 60 μl Stop/Detection Buffer (40 mM HEPES, pH 7.3; 10 mM EDTA; 0.125% Triton X-100; 1.25% BSA; 250 nM PhycoLink Streptavidin-Allophycocyanin (APC) Conjugate (Prozyme, San Leandro, Calif.); and 0.75 nM GSK3α anti-phosphoserine antibody (Cell Signaling Technologies, Beverly, Mass.; Cat# 9338) labeled with europium-chelate (Perkin Elmer, Boston, Mass.). The reaction was allowed to equilibrate for 2 hours at 22° C., and relative fluorescent units were read on a Discovery plate reader (Packard Biosciences). Inhibitor compounds are assayed in the reaction described above, to determine compound IC50s. 1 μL of compound dissolved in DMSO was added to each 40 μL reaction in a half-log dilution series covering a range of 1 nM to 100 μM. Relative phospho substrate formation, read as HTRF fluorescence units, is measured over the range of compound concentrations and a titration curve generated using a four parameter sigmoidal fit.

Specific compounds of the instant invention were tested in the assay described above and were found to have IC₅₀ of ≦50 μM against substrate.

Example 5 Inhibition of CHK1 Autophosohorylation in Cells

Inhibitor compounds are assayed for their ability to inhibit CHK1 in cells by monitoring CHK1 autophosphorylation in response to DNA damage. H1299 cells (ATCC, Manassas, Va.) are grown in culture medium: RPMI 1640 supplemented with 10% fetal bovine serum; 10 mM HEPES; 2 mM L-glutamine; 1× non-essential amino acids; and penicillin-streptomycin. Cells from T-75 flasks are pooled, counted, seeded into 6 well dishes at 200,000 cells per well in 2 ml media, and incubated. Serial dilution series of compounds in DMSO or DMSO control are added to each well from a 1000× working stock in DMSO and incubated for 2 hr at 37° C. Following the 2-hr incubation period, 100 nM camptothecin (EMD Biosciences, San Diego, Calif.) is added from a 200× working stock in PBS to all drug-treated cells (except one of the high dose wells) and one DMSO control well. After a 4 hour incubation with camptothecin, each well is washed once with ice-cold PBS and 300 μL of lysis buffer (50 mM Tris (pH 8.0), 150 mM NaCl, 50 mM NaF, 1% NP-40, 0.5% Deoxycholic acid, 0.1% SDS, 0.5 μM Na₃VO₄ and 1× Protease Inhibitor Cocktail Complete—without EDTA (Roche Diagnostics, Mannheim, Germany)) is added to each well. Plates are shaken at 4° C. for 10-15 min and lysates are then transferred to 1.5 ml microcentrifuge tubes and frozen at −80° C. Lysates are thawed on ice and cleared by centrifugation at 15,000×g for 20 min and the supernatants are transferred to clean tubes.

Samples (20 μL) are prepared for gel electrophoresis by addition of 5 μL of 5× sample loading buffer and heat-denaturation for 5 min at 100° C. Samples are electorphoresed in Tris/Glycine SDS-polyacrylamide gels (10%) and proteins are transferred onto PVDF. Blots are then blocked for 1 hr in 3% BSA in TBS and probed using an antibody against phospho-Ser-296 CHK1 (Cell Signaling Technologies—Cat #2346). Bound antibody is visualized using a horseradish peroxidase conjugated secondary antibody (goat anti-rabbit Jackson Labs—Cat# 111-035-046) and enhanced chemiluminescence (ECL-plus, Amersham, Piscataway, N.J.). After stripping of the first antibody set by incubation in 62.5 mM Tris HCl pH 6.7, 2% SDS and 2-mercaptoethanol to 100 μM for 30 min at 55° C., blots are re-probed for total CHK1, using a CHK1 monoclonal antibody (Santa Cruz Biotechnology Inc., Cat# SC-8408). The CHK1 monoclonal is detected using a sheep anti-mouse IgG coupled to horseradish peroxidase (Amersham Biosciences, Piscataway, N.J., Cat#NA931) and enhanced chemiluminescence (ECL-plus, Amersham). ECL exposed films are scanned and the intensity of specific bands is quantitated with ImageQuant software. Titrations are evaluated for level of phospho-CHK1 (Ser296) signal normalized to total CHK1 and IC50 values are calculated.

Example 6 Functional Activity of Inhibitors in Checkpoint Escape Assay DNA Damage Arrest

To measure functional activity of CHK1 inhibitors in cells, compounds are assayed for their ability to abrogate DNA damage induced cell cycle arrest. The assay determines cell phosphonucleolin levels as a measure of the quantity of cells entering M-phase after cell cycle arrest brought on by the DNA damaging agent camptothecin.

H1299 cells (ATCC, Manassas Va.) are seeded at a density of 5000 cells/well in RPMI640 media supplemented with 10% fetal bovine serum. After incubation for 24 hours at 37° C. at 5% CO₂, camptothecin is added to a final concentration of 200 nM and incubated for 16 hours. An equal volume of a test compound serial dilution series in growth media plus 200 nM camptothecin and 332 nM nocodozole (final concentration: 50 ng/ml) is added and incubation at 37° C. is continued for 8 hours-Media is removed from the wells and 50 μL lysis buffer (20 mM HEPES, pH7.5, 150 mM NaCl, 50 mM NaF, 1% Triton X-100, 10% Glycerol, 1× Proteinase Inhibitor Cocktail (Roche Diagnostics, Mannheim Germany), 1 μl/ml DNase I (Roche Diagnostics), 300 μM Sodium Orthovanadate, 1 μM Microcystin (Sigma, St. Louis, Mo.) added. The plate with lysis buffer is shaken for 30 min at 4° C. and frozen (−70° C.) for 20 min. Levels of phosphonucleolin in the cell lysates is measured using the IGEN Origen technology (BioVeris Corp., Gaithersburg, Md.).

Detection of Phosphonucleolin in Cell Lysates

4E2 anti-nucleolin antibody (Research Diagnostics Inc., Flanders, N.J.) was biotinylated using Origen Biotin-LC-NHS-Ester (BioVeris Corp.) using the protocol described by the manufacturer. Goat anti-mouse antibody (Jackson Immuno Research, West Grove, Pa.) was ruthenylated employing a ruthenylation kit (BioVeris Corp.; cat# 110034) according to the protocol described by the manufacturer. To each well of a 96-well plate is added 25 μL of antibody buffer (phospho buffered saline pH7.2, 1% bovine serum albumin, 0.5% Tween-20) containing 2 μg/ml biotynylated 4E2 anti-nucleolin antibody and 0.4 mg/ml streptavidin coated paramagnetic Dynabeads (BioVeris Corp.) along with 25 μL of cell lysate (above). The antibodies and lysate are incubated with shaking for 1 hr at room temperature. Next, 50 ng of anti-phosphonucleolin TG3 antibody (Applied NeuroSolutions Inc., Vernon Hills, Ill.) in a volume of 50 μL of antibody buffer (above) are added to each well of the lysate mix and incubation is continued for 30 min at room temperature. Lastly, 25 μL of a 240 ng/ml solution of the ruthenylated goat anti-mouse antibody in antibody buffer is added to each well and incubation continued for 3 hours at room temperature. The lysate antibody mixtures are read in a BioVeris M-series M8 analyser and EC50s for compound dependent increases in phosphor-nucleolin are determined.

Example 7 Other Biological Assays

CHK1 Expression and Purification: Recombinant human CHK1 can be expressed as a fusion protein with glutathione S-transferase at the amino-terminus (GST-CHK1) using standard baculovirus vectors and a (Bac-to-Bac®) insect cell expression system purchased from GIBCO™ Invitrogen. Recombinant protein expressed in insect cells can be purified using glutathione sepharose (Amersham Biotech) using standard procedures described by the manufacturer.

CHK1 Fluorescense Polarization Assays: CHK1 kinase inhibitors can be identified using fluorescence polarization to monitor kinase activity. This assay utilizes 10 nM GST-CHK1 and contains 5 mM 2-(N-Morpholino)ethanesulfonic acid (MES, pH 6.5), 5 mM magnesium chloride (MgCl₂), 0.05% Tween®-20, 1 μM adenosine 5′ triphosphate (ATP), 2 mM 1,4-Dithio-DL-threitol (DTT), 1 μM peptide substrate (Biotin-ILSRRPSYRKILND-free acid) (SEQ ID NO: 19), 10 nM peptide substrate tracer (Fluorescine-GSRRP-pS-YRKI-free acid) (pS=phosphorylated-Serine) (SEQ ID NO: 20), 60 ng anti-phospho-CREB(S133) mouse monoclonal IgG purified on Protein G sepharose from crude mouse ascites purchased from Cell Signalling Technologies (Beverly, Mass.), 4% dimethyl sulfoxide (DMSO) and 30 μM inhibitor compound. Reactions are incubated at room temperature for 140 minutes and terminated by addition of 25 mM EDTA (pH 8.0). Stopped reactions are incubated for 120 minutes at room temperature and fluorescence polarization values determined using a Molecular Devices/LJL Biosystems Analyst™ AD (Sunnyvale, Calif.) with standard fluorescine settings.

CHK1 SPA Filtration Assay: Assays (25μ.) contain 10 nM GST-CHK1, 10 mM MES, 2 mM DTT, 10 mM MgCl₂, 0.025% Tween®-20, 1 μM peptide substrate (Biotin-ILSRRPSYRKILND-free acid) (SEQ ID NO: 19), 1 μM ATP, 0.1 μCi ³³P-γ-ATP (New England Nuclear, NEN) and are reacted for 90 minutes at room temperature. Reactions are terminated by adding 55 μl of phosphate buffered saline containing 50 mM EDTA, 6.9 mM ATP, 0.5 mg Scintilation proximity assay (SPA) beads (Amersham Biosciences). Peptide substrate is allowed to bind beads for 10 minutes at room temperature followed by filtration on a Packard GF/B Unifilter plate and washed with phosphate buffered saline. Dried plates may are sealed with Topseal™ (NEN) and ³³P incorporated to peptide substrate using a Packard Topcount® scintillation counter with standard settings for ³³P.

CHK1 FlashPlate® Kinase Assay: Assays (25 μl) contain 8.7 GST-CHK1, 10 mM MES, 0.1 mM ethylene glycol-bis(β-aminoethylether)-N,N,N′,N′-tetracetic acid (EGTA, pH 8.0), 2 mM DTT, 0.05% Tween 20, 3 μM peptide substrate (Biotin-ILSRRPSYRKILND-free acid) (SEQ ID NO: 19), 1 μM ATP, 0.4 μCi 33P-γ-ATP (NEN) and 4% DMSO. Reactions are incubated for 30 minutes at room temperature, terminated with 50 μl of 50 mM EDTA. 90 μl of reaction is transferred to streptavidin-coated FlashPlates® (NEN) and incubated for 1 hour at room temperature. Plates are washed with phosphate buffered saline containing 0.01% Tween-20 and 10 mM sodium pyrophosphate. Plates are dried, sealed with Topseal™ (NEN) and an amount of ³³P incorporated into the peptide substrate measured using a Packard Topcount® NXT™ scintillation counter with standard settings.

CHK1 DELFIA® Kinase Assay: Assays (25 μl) utilize 6.4 mM GST-CHK1 containing 25 mM Tris, pH 8.5, 20% glycerol, 50 mM sodium chloride (NaCl), 0.1 Surfact-Amps® 20, 1 μM peptide substrate (Biotin-GLYRSPSMPEN-amide) (SEQ ID NO: 21), 2 mM DTT, 4% DMSO, 12.5 μM ATP, 5 mM MgCl₂ and are reacted for 30 minutes at room temperature. Reactions are terminated with 100 μl Stop buffer containing 1% BSA, 10 mM Tris, pH 8.0, 150 mM NaCl and 100 mM EDTA. Stopped reactions (100 μl) are transferred to 96 well neutravidin plates (Pierce) to capture the biotin-peptide substrate during a 30 minute room temperature incubation Wells are washed and reacted with 100 μl PerkinElmer Wallac Assay Buffer containing 21.5 ng/ml anti-phospho-Ser216-Cdc25c rabbit polyclonal antibody from Cell Signalling Technology (Beverly, Mass.) and 292 ng/ml europium labeled anti-rabbit-IgG for 1 hour at room temperature. Wells are washed and europium released from the bound antibody by addition of Enhancement Solution (100 μl) (PerkinElmer Wallac) and detected using a Wallac Victor2™ using standard manufacturer settings.

Compounds of the present invention may be tested in the CHK1 FlashPlate® Kinase Assay described above.

WST Assay: HT29, HCT116 (5000 cells/well) or other cells are seeded (75 μl) to 96 well clear bottom plates at densities which provide linear growth curves for 72 hours. Cells are cultured under sterile conditions in appropriate media and for HT29 and HCT116 this media is McCoy's 5A containing 10% Fetal Bovine Serum (FBS). Following the initial seeding of cells, cells are incubated at 37° C., 5% CO₂ from 17 to 24 hours at which time the appropriate DNA damaging agents (camptothicins, 5-fluorouracil and etoposide) are added at increasing concentrations to a point which is capable of causing at least 80% cell killing within 48 hours. Final volume of all DNA damaging agent and compound additions are 25 μl. Assays contain <1% DMSO final. At the same time as DNA damaging agent addition, CHK1 inhibitor compound is added at fixed concentrations to each DNA damaging agent titration to observe enhancement of cell killing. Cell viability/cell killing under the conditions described above are determined by addition of WST reagent (Roche) according to the manufacturer at 47 hours following DNA damage and CHK1 inhibitor compound addition and following a 3.5 hour or 2.5 hour incubation at 37° C., 5% CO₂ wherein OD₄₅₀ is measured.

Compounds of the present invention may be tested in the assays described above.

Example 8 Other Biological Assays

Other assays that may be utilized to determine biological activity of the instant compounds include assays found in the following publications: WO 04/080973, WO 02/070494, and WO 03/101444.

Example 9 Blood Pressure Assay

The assay is designed to evaluate acute changes in blood pressure (BP) and heart rate (HR) during i.v. infusion of compounds in conscious rats. Following vehicle, three compound concentrations are each infused for 20 minutes in a dose-escalating protocol at a rate of 25 μl/min. Blood samples are obtained at the end of each infusion (20 min.) for drug level determination and mean BP and HR are analyzed during the last 3 minutes of each infusion (17-20 min.).

Specific compounds of the instant invention were tested in the assay described above. 

1. A compound of the Formula A:

wherein: R¹ is independently selected from H and F, wherein at least one of R¹ is F; or a pharmaceutically acceptable salt or a stereoisomer thereof.
 2. A compound according to claim 1 which is: 5-(3-amino-2-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; 5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; 5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; and 5-(3-amino-2,2-difluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; or a pharmaceutically acceptable salt or a stereoisomer thereof.
 3. An HCl salt of a compound according to claim 1 which is: 5-(3-amino-2-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; 5-(3-amino-2-(R)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; and 5-(3-amino-2-(S)-fluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; or a stereoisomer thereof.
 4. A TFA salt of a compound according to claim 1 which is: 5-(3-amino-2,2-difluoropropyl)-3-methyl-2,5,7,8,9,10-hexahydro-4H-benzo[g]pyrazolo[4,3-c]quinolin-4-one; or a stereoisomer thereof.
 5. A pharmaceutical composition comprising a pharmaceutical carrier, and dispersed therein, a therapeutically effective amount of a compound of claim
 1. 6. The use of the compound according to claim 1 for the preparation of a medicament useful in the treatment or prevention of cancer in a mammal in need of such treatment. 